Background Checks and Mass Shooters, How Did They Get Their Guns?

How Did Mass Shooters Get Their Guns? Moreover, Did They Pass Background Checks?

We looked at 26 mass shootings for roughly 12 years between 2009 through 2021, in which we know how the shooters obtained their firearms. Additionally, we did not cherry-pick these incidents because it would help us establish a narrative that background checks are imperfect.

The law currently requires background checks for any gun sold through a Federal Firearm's Dealer (FFL). This requirement applies to both large and small gun stores. However, not all states require private party gun sales to go through an FFL for a background check. For a deeper understanding of background checks and universal background checks, please consider reading this content.

gun control laws are bad

Many people say they want universal background checks. Does the system work?

I know some of you want to get right into the numbers. So, in summary, here they are:

Analyzing the numbers, we find that of 25 mass shooting incidents:

  • Twenty-three (23) killers passed NICS background checks.
    • 4 Killers should not have passed background checks. Law enforcement failed to enter their criminal offenses into the database. Therefore they passed the background check. Important to note is that they also lied on the ATF Form 4473. (incidents #'s #11, #12, #17, and #19)
  • 2 Did not pass a NICS background check, and both got the gun from the family home.
    • In one instance, the killer would have passed a background check (incident #7)
    • For the second, the father of the killer purchased the gun. He should not have been able to pass the NICS check, but Law Enforcement never entered the information (incident #10). The killer took the gun from the house. In this instance, the actual killer would not have been able to pass a background check, as he was too young to purchase the handgun.
mass shooters and background checks

The 25 incidents spanned twelve years, from 2009 to 2021. We only included mass shootings where we found information on how the killer got the gun.

Killers used the following firearms:

  • handguns 16 times
  • rifles twelve times
    • ten AR-15's
    • one AK-47
    • one .22LR, bolt-action Savage MKII, rifle
  • shotguns two times
mass shooters and their guns

Methodology: if someone used 2 handguns, it is counted as 1 instance of a handgun being used. If they used a handgun and rifle, one mark is given to the handgun and one mark to the rifle. If they bought a rifle and handgun but only used the handgun, no mark is given to the rifle, only to the handgun.

You will see some commonalities between the killers. However, we do not want to generalize them all as being the same.

For example, most of them had diagnosed or undiagnosed mental and behavioral issues. I find it dangerously and factually incorrect to say anyone with mental health or behavioral person will commit a mass shooting.

Importantly, many of them had known drug addictions and held radical political or religious views. These factors have a higher correlation to violence.

That is not to say that either of these ‘red flag' commonalities in it of themselves would show someone is likely to kill people.

In other words, the problem is that there are hundreds of millions of Americans who may fit one or more of those descriptions but have not and would not kill anyone.

With this in mind, we come back to the original question.

Do background checks keep mass shooters from getting firearms?

If you are not super familiar with universal background checks, consider reading this piece.

Gun Background Checks

Here is what happens when an FFL runs a NIC's check on a potential gun buyer.

First Things First:

First, I will not be referring to the killer's names in this post. Instead, I will only mention the locations and other relevant facts of the incident.

Second, I am looking at shootings where three or more people died, not counting the attacker(s).

Thirdly, I am sticking to mass shootings where we know definitively how the killer(s) acquired their guns. Obviously, we cannot determine if a background check would have stopped them from getting the firearm if we don't know how they obtained it.

fake news

Many news organizations use the killer's name in their reporting. We will not use any killer's name in this article.

How Did The Killers Get Their Guns?

1. April 3, 2009: Binghamton New York shooting where 13 people died.

The suspect, a naturalized immigrant, fired 98 rounds from two 9mm handguns. He used a Beretta 92 FS and Beretta PX4 Storm to murder his victims and ultimately killed himself.

The shooter purchased both guns legally. He passed a background check for one of the handguns. The shooter's second NICS check returned a ‘delayed' response. This response occurs at times and provides that the transfer can only continue under one of two conditions.

  1. The NICS system eventually returns a result of ‘proceed.'
  2. The NICS system does not return any result for three days.

If either of those things happens, the sale can continue.

As in the first background check, the second NICS check did not return a ‘denied' response. After the three-day waiting period, the father obtained the gun. Further investigation showed that even if the delay had been ten days instead of 3 days, he would have passed the background check because he was not prohibited.

mass shooting

Binghamton, NY mass shooting: Photo courtesy of NY Times

2. November 5, 2009: Terrorist kills 13 people at Fort Hood Army Base in Texas.

The suspect, a Major in the United States Army, killed 13 people and wounded 43 others. He used an FN Five-SeveN series handgun.

About a year before the murders, federal authorities intercepted text messages between the shooter and a radical Muslim leader known for anti-American beliefs. The killer legally purchased the gun at a gun store and passed a background check.

3. January 8, 2011: Tucson, Arizona shooting that killed six people.

The suspect had no prior mental issues or significant criminal offenses. He bought a Glock 19, 9mm handgun to murder six people in a supermarket parking lot. The shooter legally purchased the pistol in a gun store after passing a background check. The judge ruled the killer incompetent to stand trial after being diagnosed as schizophrenic. This incident is where Representative Gabrielle Giffords was injured.

representative gabby giffords

Arizona Representative Gabby Giffords

4. April 2nd, 2012: Loner murders seven people at Oikos University in Oakland, California.

The shooter was considered anti-social but had no known mental issues or criminal offenses before the killing. He passed a background check and legally purchased a Springfield Armory XD 9mm handgun at a local gun store. After the shooting, he was diagnosed with paranoid schizophrenia and found not fit for trial.

5. July 20, 2012: Aurora, Colorado movie theater shooting, killing twenty-four people and wounding 12.

The killer purchased four firearms 60 days before the shooting. He bought the four firearms on two separate trips to gun stores. He passed a background check and legally purchased 2 Glock 22 .40 caliber handguns, a pump-action, Remington 870 shotgun, and a Smith and Wesson M&P15 AR rifle.

The killer saw a psychiatrist before the shooting. Still, none of the issues were severe enough to prevent him from legally purchasing a firearm. He is in prison for life after entering a plea of not guilty because of insanity.

movie theater shooting

The killer used incendiaries and came prepared with body armor during his killing in a Colorado movie theater.

6. August 5, 2012: A man kills six people at a Sikh Temple in Oak Creek, Wisconsin.

The killer was a former Army veteran and had known ties to a racist white-power music band. He passed a background check and legally purchased a Springfield Armory XD handgun. The pistol was used to kill six people and wound three others.  Police shot the suspect and stopped him from continuing. However, he died from a self-inflicted gunshot wound before law enforcement could take him into custody. The motivation is assumed to be racial hatred. However, this was never confirmed as he left behind no manifesto.

police mass shooting sandy hook


7. December 14, 2012: A mass shooter kills his mother and then 26 others at Sandy Hook Elementary School in Newtown, Connecticut.

The killer did not purchase the guns at a store or through private party transfer. He accessed the firearms that were in his family's gun safe. The shooter was of legal age to possess the guns and would have passed a background check. Additionally, at the time of purchase, he could own firearms legally. He used a Bushmaster XM-15 .223, an AR-15 rifle, and a .22LR Savage Mark II bolt-action rifle in his mass killing. Although he had an obsessive-compulsive mental disorder, his mother did not believe it was of any concern and did not prohibit him from using the firearms.

8. September 16, 2013: Washington, DC. Navy Yard shooting, killing twelve and injuring three others.

After four years, a Navy Reservist was honorably discharged. While serving, he had medical treatment for psychiatric issues but never committed to a mental facility. Later on, he was unable to purchase a handgun at a local gun store because of a federal law that requires that firearms only be sold to residents of the state.

After passing a background check, he purchased a Remington 870 shotgun. This is the firearm he used in the mass shooting. Responding officers ultimately shot and killed him.

9. April 2, 2014: Killer armed with pistol kills three people and wounds 16 at Fort Hood, Texas Army Base.

Army doctors were treating the killer for depression and anxiety. Some speculate that he had post-traumatic stress disorder (PTSD) from a recent deployment to Iraq, even though he never saw combat. The killer passed a background check and legally purchased a Smith and Wesson 9mm handgun from the same store the other Fort Hood killer purchased his gun.

mass shooting act of terrorisim

Photo of mourning soldiers after the mass shooting at Fort Hood Army Base by a terrorist.

10. October 24, 2014: Teenager kills four students at a high school in Marysville, Washington.

In this incident, the killer's father was prohibited legally from purchasing firearms due to a domestic violence arrest 12 years earlier. However, the arrest did not show up on the background check, and he bought four guns and passed the background check. He also lied on the ATF application 4473 when purchasing the firearm.

After the mass shooting, police arrested the father of the killer for gun violations. The killer accessed a Beretta PX4 Storm .40 cal handgun that his father had and used it to kill four classmates before killing himself at the scene.


CHARLESTON, SC mass shooting


11. June 17, 2015: South Carolina Church shooting where suspect killed nine people.

Before the shooting, the police arrested the killer possessing Suboxone. This arrest did not show up in the background check he passed when he purchased a Glock 41 .45 ACP handgun at a local gun store. He also lied on the ATF application form 4473 when purchasing the handgun. This arrest would have prohibited him from buying a firearm. The killer was racist and targeted black people at the church to create a race war.


mass shooting

12. July 23rd, 2015: Man purchases handgun and uses it to kill two people, wounding nine others in a Lafayette, Louisiana movie theater.

The killer had been denied a concealed carry license due to accusations of domestic violence and arson solicitation. The judge sent the killer to a psychiatric hospital for a mental health evaluation. Family members said he supposedly had bipolar disorder. The killer passed a background check and lied on the ATF Form 4473. He purchased the Highpoint .40 cal handgun at a local pawn shop. He was able to pass the NICS check because he had not been committed to a mental health facility, instead just evaluated.

13. October 1, 2015: Man shoots and kills nine people at Community College in Umpqua, Oregon.

The Army discharged the eventual killer before he completed Army basic training. He had a history of behavioral problems but had no significant criminal record. The killer legally purchased and passed background checks for several of the 14 firearms that he owned. Family members also passed background checks at the time of purchase.

The killer used two handguns during the shooting, a Glock 19 and a Taurus PT 27/7. He also had two more handguns and a Del-Ton AR-15 with him. Although the killer arrived with body armor, multiple guns, and ammunition, two officers quickly killed him before he could transition to the rifle or other handguns.

college mass shooting

Umpqua, Oregon Community College Shooting

14. December 2, 2015: ISIS Terrorist, Husband, and wife killed 14 people in San Bernardino, California.

FBI spokesman claim that the husband and wife had been part of a radical Islamic ideology for quite some time before the shooting. However, the FBI said the couple was not on the FBI's radar as terrorists. The husband passed a background check and legally purchased two 9mm 1911 handguns.

The couple also used two .223 AR-15 rifles that a relative of the couple passed a background check and legally purchased. The relative ultimately was convicted of gun charges for giving the guns to the killers and not legally transferring them to him through an FFL. However, the relative could have legally transferred the firearms to the killer. Additionally, the killer would have passed a background check if he decided to purchase the guns in a store.

15. June 12, 2016: A man kills 49 people in an Orlando, Florida nightclub with a rifle and handgun.

The killer passed a NICS background check and legally purchased two firearms, a Glock 17 handgun and Sig Sauer MCX AR-15 rifle. The killer, whom FBI agents identified as having followed a radical Islamic ideology, killed 49 people and injured another 53 people. The murderer was ultimately shot and killed by the police on the scene.

16. October 1, 2017: A single man uses several different AR-15 to fire into a crowd from a 32nd-floor hotel room in Las Vegas, Nevada, killing 58 people and wounding 500 others.

A man whose motivations are still unknown planned a mass shooting at a concert in Las Vegas, Nevada. He booked a 32nd-floor room in an adjacent hotel that overlooked a group of concertgoers. The killer had over 20 firearms in the hotel room and used at least 2 AR-15 rifles to fire down into the crowd. Police found twelve of the rifles equipped with a “bump stock” device.

Investigators determined that each firearm seized was legally purchased and owned. As in other incidents, the murderer killed himself rather than stand trial for his actions.

The shooter had tactical advantages beyond the rate of fire of his rifles, which made this incident especially deadly.

17. November 5, 2017: A man enters a church in Sutherland Springs, Texas, and uses a rifle to kill 26 people. The killer was struck by fire by a church member and fled the scene. Police found the killer dead in his vehicle.

The killer was an Air Force veteran. Police investigated an assault where he fractured his child's skull and assaulted his wife, which resulted in a criminal conviction. He received a bad-conduct discharge from the military. Two years after his release, he passed a NICS background check on two separate occasions to purchase firearms.

One of which, a Ruger AR-15 rifle he used in the mass-killing. His domestic violence conviction was enough to bar him from possessing or purchasing a firearm legally.

However, the Air Force never entered it into the NICS system, and therefore, he passed both background checks. He also lied on the ATF firearm application form 4473, which asks about domestic violence convictions.

NRA Firearms instructor and church member Steven Willeford used an AR-15 rifle he had in his vehicle to shoot the killer from a distance. Police believe that the killer was likely targeting more churches. This is because, in addition to his dead body, they found much more ammunition and firearms in the car. Fortunately, he died before he was able to carry out more attacks.

18. February 14, 2018: Disturbed student shoots and kills 17 people at his High School in Parkland, Florida.

A 19-year-old student with behavioral issues passed a NICS background check and legally purchased a Smith and Wesson M&P AR-15 rifle. An acquaintance warned the FBI of the killer and his desire to kill people. Additionally, the informant told the FBI that the killer could be a future school shooter. The FBI admitted it received but never acted upon the information.

The event lasted roughly 6 minutes. This incident brought to light clear evidence of a massive, systemic problem in training and response protocol within the Broward Sheriff's Department. The killer survived, and police later found evidence that his motivations stemmed from a hatred of people. Being a mass killer would make him notorious.

parkland florida shooting

19. August 4, 2019: A man uses a rifle to kill 9 people and injuring 17 others outside a bar in Dayton, Ohio.

A self-described ‘leftist' infatuated with Antifa and becoming a mass killer, passed a background check and purchased an AR-15 rifle. He lied on the ATF firearm application form 4473, as he was a known drug user. It is not known why the killer chose the people or location for this shooting. Of interest is that police were already on the scene. They shot and killed him only 32 seconds after the first shot was fired.

police response to Dayton ohio mass shooting

Dayton, Ohio

20. May 31, 2019: A Man uses two handguns to murder his wife and 11 others in Virginia Beach shooting.

In roughly 3 years before the shooting, the killer passed NICS background checks and legally purchased 6 firearms. He used two handguns in the shooting, a .45 ACP Glock 21 and H&K USP Compact. The H&K handgun was equipped with a suppressor, commonly referred to as a silencer.

He legally purchased the suppressor and passed the enhanced background check required to purchase one. The killer appeared to have some workplace issues and resigned from his job at the city's Public Utilities department before the shooting.

21. July 9th, 2019: A man uses a rifle to kill 3 people, injuring 12 others at an outdoor garlic festival in Gilroy, California.

A man passed a NICS background check and legally purchased an AK-47 rifle that he used to kill people at the festival. There is some indication that the killer may have been a racist. However, based on the victims, it does not appear that was the motivation behind the killing. However, it is reported that when asked why he was shooting people, he said, “because I am really angry.”

The killer was shot and killed by police in under a minute. Police happened to already be on the scene when the killer began shooting.

22. December 10, 2019: Two anti-Semitics use rifles to kill 3 people, two of which were police officers, inside a Kosher deli in Jersey City, New Jersey.

A man and woman identifying themselves as Black Hebrew Israelites used two AR-15 rifles in the shooting. The male killer passed a NICS check and legally purchased the 2 rifles roughly a year before the shooting. There was some confusion about how the couple came into possession of the firearms used in the attack. This came because police found a business card from a local pawn shop owner on the male killer's dead body.

An investigation showed that the pawnshop owner, Ahmed A-Hady, was illegally selling firearms from his pawnshop. Ultimately, police determined that the killers did not get the firearms they used from A-Hady. However, the killers had help with elaborate preparation for the killing and other attacks on Jews. It is unknown, and we are not alleging that A-Hady had any larger involvement with the couple.

mass shooting

23. December 26, 2020: Active-Duty Army Special Forces Soldier uses two handguns to shoot and kill 3 people and injure 3 others at a bowling alley in Rockford, Illinois.

An active-duty Army Special Forces Soldier passed background checks and legally purchased the two Glock handguns he used in the attack. One was a .380 caliber, and the other .40 caliber. The killer had no known indication of behavioral or mental issues before the shooting. Speculation arose that he may have developed PTSD during one of his 4 combat deployments to Afghanistan. The killer had earned a bronze star for valor in combat. No known motivation has been identified at this time.

24. March 16, 2021: Male killer uses a handgun to kill 8 people at massage parlors in Atlanta, Georgia.

Police took the male killer into custody, and a 9mm handgun used in the killings was recovered. The killer passed a NICS background check and legally purchased the handgun. The killer said the killer's motivation came from a sexual addiction he had. Afterward, he associated blame with the Asian women he targeted in his attack.

25. March 22, 2021: Male killer uses a ‘patrol rifle' to kill 10 people at a King Soopers supermarket in Boulder, Colorado.

A male killer passed a background check and legally purchased the Ruger AR-15 rifle he used in his attack. Additionally, the attacker had a handgun with him during the attack. However, for an unknown reason, he did not use it. Details about the killer are still emerging. However, police have confirmed that he was the suspect in a third-degree assault in 2017 and a criminal mischief report in 2018. It is unclear what the dispositions of either of those cases are at this time. A conviction, however, in either case, would not have been grounds to strip him of his right to purchase a firearm legally.

There is some indication the killer had a political and ideological motivation behind the attack. However, the actual motivation is still unknown.

vboulder colorado shooting


Here is where I will present my opinion:

I do not think they can.

For Universal Background Checks to Be Effective:

  • First and foremost must be truly universal. That is to say, that every single gun sale must go through an FFL. This includes criminals who buy firearms or a family member selling or giving a firearm to another family member.
  • All arrest information must be accurate and entered promptly.
  • Every single law enforcement agency in the entire country must participate by entering the relevant information.
  • The ATF must investigate instances of a ‘delayed' NICS result and clarify the issue immediately.

It is also my opinion that if the ATF wants to regulate businesses that sell firearms, they have the legal grounds to do it furthermore, if that requires that FFL's conduct NICS background checks, so be it.

NICS universal background checks

What authority do the individual states have?

If individual states want to pass laws that prohibit private party sale of firearms without them going through an FFL, that is likely within their authority.

However, I believe it to be an overreach of the federal government to require all private individuals who sell a firearm to first take it to an FFL for a NICS background check on the buyer. Additionally, I think it only hinders law-abiding citizens who would follow such a law in the first place. Furthermore, it opens the door to an inevitable federal registration database of firearm owners.

About Matthew Maruster

I follow my Lord and Saviour Jesus Christ who is the eternal co-equal Son of God. I currently live in Columbus, Ohio with my wife and daughter. I served in the Marine Corps Infantry. I was a Staff Sergeant and served as a Platoon Sergeant during combat in Iraq. After I was a police officer at a municipal agency in San Diego County. I have a Bachelors's Degree in Criminal Justice from National University. MJ Maruster Defense.


  1. Bryan on April 20, 2021 at 5:53 pm

    Great article!!!

  2. Shane on April 22, 2021 at 7:37 am

    Great information Matthew! I would have expected there to be way more AR-15’S used than anything else but clearly that’s just the portrayed image of the media and anti-gunners.

  3. Russell Thomas on April 22, 2021 at 6:38 pm

    If you think police agencies are bad about putting the initial “arrest” information in to the system. The updating after not prosecuting, found not guilty or otherwise discharged is nonexistent in many jurisdictions. There is no motivation or requirement for police agencies to respond if no problem exist ….. after the wait period (3-10 days) the sale goes through automatically. My last LEO family member is quitting/retiring in disgust of modern policing.

  4. Murray on June 7, 2022 at 8:36 am

    A lot of words and data to justify putting holes in people’s bodiy’s Who cares what gun is used (semi-auto, automatic, miliitary of non-military grade, small or large calibre, hand or rilfle). Bottom line – they can all kill people and there are far more out there than is needed. Why are we trying to justify the possession of guns by comparing them to other horrible methods of causing murder. It is so interesting that the abuse of guns is used to promote the sale of more guns so people can protect themselves – this is the definition of a viscous cycle. I hope you realize that your “clarification” of the data does nothing to solve the problem.

    • Matthew Maruster on June 7, 2022 at 9:20 am

      Thanks for your point of view Murray. I can’t solve the problem of sin and evil, only Jesus can do that. I can however protect myself ond others against evil people who would murder.

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