A large majority of guns used in school shootings since 2008 were brought to campus from the teenage assailant’s home or a family member’s residence, according to a federal law enforcement report released Thursday afternoon.

Nineteen of the 25 attackers — 76% — used a gun obtained from a parent or close relative in his or her attack on students, school staff, and others in incidents between 2008 and 2017, the U.S. Secret Service wrote in a report, "Protecting America’s Schools: A U.S. Secret Service Analysis of Targeted School Violence." Attackers used handguns, rifles, and shotguns in the attacks, including sometimes more than one weapon.

Of those 25 shooters, all ages 12 to 18 at the time of the incident, nearly half said the gun they used was “readily accessible” or was left unsecured. In some cases, shooters found the guns in an unlocked cabinet, locked in a vehicle, or hidden in a closet.

Eight of these school shooters took possession of the gun the day they carried out the attack, while four acquired a gun the day before. Others found a gun in the days or weeks leading up to the day of the incident.

Federal law prohibits those under the age of 18 from possessing a handgun except in rare situations. However, Secret Service’s National Threat Assessment Center writes in the report, “Federal law does not restrict the age of individuals who may possess long guns (e.g., shotguns and rifles).”

The report looked at 41 total incidents committed by 41 assailants between 2008 and 2017. It was commissioned in early 2018 and thus did not look at the February 2018 Marjory Stoneman Douglas High School shooting in Florida or May 2018 shooting at Santa Fe High School in Texas.

Sixteen of the 41 attackers did not use guns but instead pulled bladed weapons on their peers. The Secret Service reported butcher knives, hunting knives, and pocket knives were among the types of knives used.

Thirty-two attackers were criminally charged, including 22 who were charged as adults. Seventeen of the 22 pleaded guilty and two others pleaded no contest. Two cases went to trial, and the suspects were convicted as adults.

Twenty-two who were convicted are in prison, and one person is a patient at a mental health facility. Eight shooters have been released from juvenile jails or adult prisons.

Seven committed suicide following the attack. It's not clear what happened to the other two.