Cory Henderson, 31, faced multiple state and federal charges going back more than 10 years, according CNN affiliate KUTV
Henderson pleaded guilty to possessing an unregistered sawed-off rifle in 2005, and in 2010 pleaded guilty to felony possession of a firearm, KUTV reported. Both were federal charges.
Henderson also pleaded not guilty to federal drug and gun charges just last month, KUTV said.
A federal magistrate judge sent Henderson to a treatment center run by the Utah Department of Corrections. A representative told KUTV that Henderson walked away from the center on December 18. Law enforcement was notified and a fugitive warrant was issued.
Traffic accident and shooting
Sunday's violence began when officers from the Unified Police Department of Greater Salt Lake responded to a traffic accident and began to search for two people who had fled.
Barney, 44, found a male suspect Sunday, who then shot the officer, police said.
Additional officers responded to the scene.
There was a shootout between them and the suspect, during which Officer Jon Richey, 51, was injured and Henderson was killed, police said.
Officers Barney and Richey were taken to an area hospital, where Barney died of his injuries. He was an 18-year veteran of law enforcement.
Police said Richey was in serious condition, but improving.
"Today, a husband and father left his wife and three children, put on a badge and promised to return home soon. On behalf of Utah residents from across the state, our hearts are broken for the family of Officer Doug Barney, who gave the ultimate sacrifice today while in the line of duty," Utah Gov. Gary Herbert said in a statement.
Police spokesman Lt. Lex Bell told CNN that a female suspect has been arrested and is being questioned in connection with the shooting.
"She matches the description of a woman who was walking away from the scene of the accident, and she is one of many female acquaintances of the suspect. At this point, she is just being held for leaving the scene of an accident," Bell said.
The spokesman also said that Henderson had been wanted for a state parole violation and a federal arms violation.