Timeline: Some of the worst mass shootings in the U.S. and the world

Judy Goos, second from left, hugs her daughters friend, Isaiah Bow, 20, while eye witnesses Emma Goos, 19, left, and Terrell Wallin, 20, right, gather outside Gateway High School where witness were brought for questioning Friday, July 20, 2012 in Denver. A gunman wearing a gas mask set off an unknown gas and fired into a crowded movie theatre at a midnight opening of 'The Dark Knight Rises.' (AP / Barry Gutierrez)

The following is a timeline of some of the worst shootings in U.S. history and around the world.

2012: In April this year a lone gunman killed seven people and injured three at a small Korean Christian college in Oakland, California.

A former student, One Goh, stands accused of the massacre after a female member of staff wasn't on site when he wanted to speak with her.

This shooting became the sixth-deadliest American school massacre in history.

2011: On August 7th 2011 seven people were shot dead in Copley Township, Summit County, Ohio.

Using two handguns Michael E. Hance, 51, killed his girlfriend and six other people following a family argument.

2009: The Geneva massacre occurred on the 10th of March 2009 in Geneva and Samson, in Alabama. 11 people, including the gunman - 28-year-old Michael Kenneth McLendon were killed in the incident.

Among the victims of the massacre were members of McLendon's family. The victims were aged between 18 months and 74 years old.

2007: The Westroads Mall shooting - as it became known - started on the morning of December 5, 2007.

Nineteen-year-old Robert A. Hawkins killed himself after shooting nine other people at the Von Maur department store in the Westroads Mall in Omaha, Nebraska.

Hawkins had written in a note that he loved his friends and family, but "he was a piece of s--- all his life, and now he'll be famous."

2007: The Virginia Tech massacre is the deadliest shooting incident by a lone gunman in US history.

Seung-Hui Cho, an undergraduate at Virginia Polytechnic Institute and State University, killed 32 classmates and wounded 25 in April 16, 2007.

Cho, an English major, sent a “media pack” containing menacing images of himself to NBC on the morning of the attacks before later committing suicide.

January 2006 A woman killed seven people then herself at her former postal workplace in Goleta, California.

March 2006 A loner shot six people at party in Seattle, then himself.

2005: Dubbed the Red Lake Massacre this incident occurred on the morning of March 21st when 16-year-old Jeffrey Weise killed his grandfather and his grandfather's girlfriend before going on to kill nine people during a school spree killing.

Five students, one teacher and an unarmed security guard were killed in the incident. Five other people were injured.

The shooting is the fifth deadliest school massacre in US history.

2002: In October 2002, John Allen Muhammad and Lee Boyd Malvo killed 10 people in what would later be dubbed the Beltway sniper attacks.

The pair went on a shooting spree through Washington and Virginia, using a series of different weapons.

Muhammed was later executed for his crimes and Malvo was sentenced to six consecutive life sentences without the possibility of parole.

1999: On April 20 1999, two senior students at Columbine High School, Colorado, went on a killing spree which left 12 students and one teacher dead.

Eric Harris and Dylan Klebold also injured 21 other students before committing suicide.

The shootings sparked debate over gun law reforms and, for one of the first times, the influence of video game violence.

July 1993 A businessman, 55, entered a law office in San Francisco and shot dead eight people, then himself.

October 1991 George Hennard drove his pickup to Luby's cafeteria in Killeen, Texas, then shot dead 23 people and himself.

February 1988 An ex-employee returned to his laboratory in Sunnyvale, California, and killed seven people, and injured three - including a woman he had been stalking

August 1986 A former postal worker entered a post office in Oklahoma, and shot 14 workers before killing himself.

July 1984 Some 21 people were killed when a 41-year-old opened fire at a McDonald's restaurant in San Diego. He was shot by police.

February 1983 Three men shot dead 14 people in the Wah Mee club in Seattle's Chinatown.

August 1966 A gunman holed up in a clocktower at the University of Texas campus in Austin killed 15 people before being shot by police.

Some of world's worst mass shootings: