A man charged with killing the operator of a speed-camera van along a motorway in north Phoenix, Arizona, has been found competent to stand trial and will not face the death penalty.

Maricopa County Superior Court Judge Michael Kemp said Thomas Patrick Destories, 69, would stand trial on July 12.

Destories' lawyer, Vanessa Smith, had written in court documents that her client has a history of mental illness dating back to 1970.

Destories is charged with murder, drive-by shooting and firing a gun in the death of Doug Georgianni.