Dale Hausner

An Arizona death row inmate convicted of killing six people in Phoenix’s “serial shooter” attacks has died in prison.

Dale Hausner, 40, was found unresponsive in his cell in Florence around noon today, prison officials say. He was pronounced dead at a hospital about an hour later.

The cause of death is under investigation, authorities say.

Hausner was sentenced to die for his convictions in a series of random shootings in the Phoenix area in 2005 and 2006.

Investigators say Hausner preyed on pedestrians, bicyclists, dogs and horses during a 14-month conspiracy that occasionally included his brother and his former roommate, Sam Dieteman.

Dieteman pleaded guilty to two of the killings.

Senior Editor, News, Arizona Daily Star, Tucson, Az.