Here's a look at what you need to know about rampage killings that have occurred in the U.S since the 1940s.
U.S. Timeline (selected only) includes incidents on college and university campuses as well as places of worship and offices.
2013 September 16, 2013 - Twelve people are killed inside the Navy Yard in Washington, DC. The shooter, identified as Aaron Alexis, 34, is also killed.
June 7, 2013 - As many as six people are killed in a random shooting rampage in Santa Monica, California, that ends in the library of Santa Monica College with the gunman dead. John Zawahri, 23, uses a rifle that the police describe as an AR-15 style gun.
March 22, 2013 - One person is killed and three others are injured during a shooting in an apartment at Gravesend Houses, a public housing project in Coney Island, Brooklyn, New York. The next day, police charge Joseph Brown, 29, with one count of murder and three counts of attempted murder.
2012 December 11, 2012 - Three people are shot at Clackamas Town Center in Happy Valley, a suburb outside of Portland, Oregon. Cindy Ann Yuille, 54 and Steven Mathew Forsyth, 45, die of their injuries. Kristina Shevchenko, 15, is severely wounded but survives. Jacob Tyler Roberts, 22, the suspected shooter, dies at the scene of a self-inflicted gunshot wound to the head. He uses a stolen AR-15 semi-automatic rifle.
August 5, 2012 - Six people are killed and four wounded when Wade Michael Page, 40, opens fire with a Springfield 9mm semi-automatic handgun at a Sikh temple in Oak Creek, Wisconsin. According to the FBI, Page died from a self-inflicted gunshot wound to the head after he was shot in the stomach by a responding officer.
July 20, 2012 - Twelve people are killed and 58 are wounded in a shooting at an Aurora, Colorado, movie theater screening of the new Batman film. James E. Holmes, 24, is taken into custody outside of the movie theater. Holmes was dressed head-to-toe in protective tactical gear, set off two devices of some kind before spraying the theater with bullets from an AR-15 rifle, a 12-gauge shotgun and at least one of two .40-caliber handguns police recovered at the scene.
April 2, 2012 - Seven people are killed and three others injured during a shooting at Oikos University in East Oakland. The suspect One Goh, 43, allegededly walks into an Oikos University classroom, lines up students against a wall and using a .45 caliber handgun, shoots them one by one. After the shooting, Goh supposedly leaves the classroom, reloads his semi-automatic weapon, and then returns. The rampage ends with the suspect driving off in a victim's car and surrendering to police a short time later. On April 30, 2012 Goh pleads not guilty to seven counts of murder and three counts of attempted murder.
2011 October 12, 2011 - Eight people are killed during a shooting at the Salon Meritage in Seal Beach, California. The suspect, Scott Evans Dekraai, 41, of Huntington Beach, is arrested without incident as he is trying to leave the scene. The eight dead include Dekraai's ex-wife, Michelle Fournier, 48. He was armed with three guns -- a 9 mm Springfield, a Smith & Wesson .44 Magnum, and a Heckler & Koch .45 -- and was wearing body armor during the shooting rampage.
October 5, 2011 - Three people are killed at the Lehigh Southwest Cement Plant in Cupertino, California when employee Shareef Allman starts shooting in a meeting. He flees the scene, but dies later of a self-inflicted head wound during a confrontation with sheriff's deputies.
January 8, 2011 - Jared Lee Loughner, armed with a Glock pistol, kills six people and wounds 13 others at a "Congress on Your Corner" event sponsored by Rep. Gabrielle Giffords (D) at a local grocery store. Giffords is shot in the head, but survives. Loughner is charged with one count of attempting to kill a member of Congress, two counts of first degree murder and two counts of attempted murder. On August 7, 2012 Loughner pleads guilty to 19 charges in exchange for the government not seeking the death penalty.
2010 August 3, 2010 - Manchester, Connecticut - Omar Thornton kills eight co-workers at Hartford Distributors before turning the gun on himself. Thornton had been asked to resign for stealing and selling alcoholic beverages.
February 12, 2010 - University of Alabama - Huntsville professor Amy Bishop Anderson, 42, shoots six colleagues during a meeting, killing three. She is charged with capital murder and three counts of attempted murder. On September 11, 2012 Anderson accepts an agreement with the state and pleads guilty to three counts of attempted murder and agrees to later plead guilty to a capital murder charge.
January 19, 2010 - Christopher Speight, 39, kills eight people at a house in Appomattox, Virginia. He surrenders to police at the scene the next morning. February 2013 he's sentenced to five life terms plus 18 years.
January 7, 2010 - Eight employees are shot, and three killed at the ABB plant in St. Louis. The gunman, who dies after turning the gun on himself, is identified as Timothy Hendron.
2009 November 6, 2009 - In Orlando, Florida, 40-year-old Jason Rodriguez is accused of killing one person and wounding five others in a shooting at an office where he once worked. He is later arrested and charged with first-degree murder. On January 11, 2012, a judge rules that Rodriguez is not competent to stand trial.
November 5, 2009 - Maj. Nidal Malik Hasan kills 13 people and injures 32 at Fort Hood, Texas, during a shooting rampage. He is charged with 13 counts of pre-meditated murder and 32 counts of attempted murder.
August 4, 2009 - In Pittsburgh, Pennsylvania, 48-year-old George Sodini, enters the L.A. Fitness club and kills three women and wounds ten others before killing himself.
June 10, 2009 - In Washington, D.C., James W. von Brunn, a white supremacist, enters the U.S. Holocaust Memorial Museum and fatally shoots a security guard, Stephen Tyrone Johns. Von Brunn is wounded by return fire from other guards. He dies in prison in Jan. 2010.
April 3, 2009 - In Binghamton, New York, Jiverly Wong kills 13 people and injures four during a shooting at an immigrant community center. He then kills himself.
March 29, 2009 - In Carthage, North Carolina, 45-year-old Robert Stewart kills a nurse and seven elderly patients at a nursing home. In May, the Moore County district attorney announces she will seek the death penalty. On September 3, 2011, a jury finds Stewart guilty of second-degree murder. Stewart is sentenced to 141 to 179 years in prison.
March 10, 2009 - In Alabama, Michael McLendon of Kinston, kills 10 and himself. The dead include his mother, grandparents, aunt and uncle.
March 8, 2009 - In Maryville, Indiana, Fred Winters, the pastor of the First Baptist Church is shot and killed during the 8 a.m. service. The attacker, Terry Joe Sedlacek suffers self-inflicted knife wounds, and also wounds two parishioners who subdue him.
2008 October 26, 2008 - At the University of Central Arkansas, four men open fire near Arkansas Hall, killing two people and wounding a third victim. Four suspects are charged in the shooting: Kawin Brockton, 19; Kelsey Perry, 19; Mario Toney, 20 and Brandon Wade, 20. Brockton, Toney and Wade plead no contest and later testify that Perry pulled the trigger. Wade is sentenced to 26 years in prison while Toney and Wade receive 18 years. Perry is sentenced to 40 years in prison.