PHOENIX - The man who shot and killed a Phoenix police detective and injured another has a long track record of violence.
The ABC15 Investigators poured through court paperwork about William Thornton’s multiple convictions.
Thornton’s first interaction with police came in 2000, when at the age of 15, he was arrested and convicted of attempted aggravated assault.
One year later, he was in trouble again, this time for marijuana possession.
Then in 2003, Thornton was sentenced to 6 ½ years in prison for armed robbery and theft.
Shortly after his release in 2009, Thornton was sent back to prison after stealing his stepfather’s truck and running from police when they tried to stop him.
In 2012, he was convicted and sentenced to more prison time for drug possession and resisting arrest.
Phoenix police say Thornton was also a suspect in an attempted murder on February 25.
In that incident, a man was shot in the back in a neighborhood near 40th Avenue and Camelback.