Here is a look at the recent cases of spree killers, mass murderers and rampage murders in the U.S.
On September 16, 2013, Aaron Alexis, 34, of Fort Worth, Texas, killed 12 people inside the Washington Navy Yard in Washington, D.C. Alexsis gained access into the Navy Yard by showing a military-contractor ID. He then entered Building 197 and went to an area above an atrium and began shooting down into a cafeteria with a semi-automatic weapon. Alexis was killed by police inside the building.
It was later determined that Alexis appeared to suffer from mental illness and a delusional belief that low frequency electromagnetic waves controlled his actions.
2. John Zawahri
Santa Monica Police
On June 7, 2013, John Zawahri, 23, killed six people, including his father and brother in Santa Monica, California.
After killing his family members, he set his father's home on fire, hijacked a SUV and armed with a .223 semi-automatic rifle
he went on a shooting spree which ended at the Santa Monica College library.
Zawahri was killed by police officers during an exchange of gunfire at the library. According to police reports, the shooting rampage was probably motivated by the divorce of his parents. Zawahri also had a history of mental health problems and according to friends, an obsession with guns.
3. Jacob Tyler Roberts
Clackamas County Sheriff's Department
On December 11, 2012, Jacob Tyler Roberts, 22, entered the Clackamas Town Center in suburban Portland, Oregon, armed with a stolen AR-15 semi-automatic rifle and clad in a white hockey mask and tactical clothing.
Upon entering the mall he began firing shots into the food court. Witnesses say that it appeared that the rifle jammed. He then fled to a stairway where he was found dead from an apparent self-inflicted gunshot.
Killed were Steven Matthew Forsyth, 45, and Cindy Ann Yuille, 54. Wounded was Kristina Shevchenko, 15. Friends, co-workers and family members described Roberts soft-spoken and kind. What motivated Roberts to go on a killing spree is unknown.
Wade Michael Page, 40, was a white supremacist and U.S. Army veteran who on August 5, 2012, went to the Sikh temple in Oak Creek, Wisconsin armed with a Springfield XD(M) 9-millimeter semi-automatic pistol. There he shot and killed six people and wounded four others. He died on the scene after being shot in the stomach by the police and then shooting himself in the head.
On July 20, 2012, James Holmes, 24, dressed as "The Joker"and in protective tactical gear, entered the Century 16 theater in Aurora, Colorado, during the midnight premiere of "The Dark Knight Rises." There he set off two tear gas canister, then fired randomly into the crowd killing 12 people and wounding 52 others. The police arrested Holmes outside of the theater after the shooting. His case is currently pending.
6. One Goh
On April 2, 2012, One Goh, 43, was arrested for allegedly killing seven people and injuring three others at Oikos University in East Oakland. According to police reports, former student One Goh entered a nursing classroom at the University and ordered the students to line up against a wall, then shot each of them with with a fully loaded, .45-caliber semi-automatic handgun. He fled the scene in one of the victim's car, then later turned himself into authorities. On April 30, 2012, Goh pled not guilty
. The case is still pending.
7. Scott Evans Dekraai
On October 12, 2011, Scott Dekraai, 41, clad in body armor and carrying several weapons, was arrested for opening fire at a salon in Seal Beach, California.
According to police, Dekraai was in a custody battle over his 8-year-old son with his ex-wife, Michelle Fournier, who worked at the salon. The two had argued over the phone the morning of the attack.
Eight people, including his ex-wife were shot and killed.
On November 29, 2011, Dekraai pled not guilty. The case is still pending.
It was the deadliest mass killing in Orange County history.