(Updates with release)
PHILADELPHIA, March 2 (Reuters) - An elderly Pennsylvania inmate convicted of shooting a police officer in 1966 but cleared of his murder when the officer died 41 years later was released on Friday on parole, state authorities said.
William Barnes served 16 years in prison for attempted murder in the shooting of Officer Walter Barclay. He was tried again but acquitted of murder after Barclay died from a urinary tract infection in 2007.
But Barnes, 75, had remained in prison on probation violations.
He was released at midday on Friday, according to a spokesman for the state Board of Probation and Parole, which issued its decision on Wednesday.
In Barnes' murder trial in 2010, prosecutors tried to argue there was a chain of direct causation between Barclay's shooting in 1966 and his death in 2007. They claimed the illnesses that caused his death were the direct result of the gunshot wounds.
Barnes shot Barclay during an attempted robbery, injuring his spine and leaving him needing to use a wheelchair.
But the defense successfully maintained that any links between the shooting and Barclay's death were broken by three car accidents, two falls from his wheelchair and neglect by nursing home staff, all of which could have contributed to ending his life.
Barnes had been out on parole briefly when he was rearrested in 2007 following Barclay's death.
(Editing By Ellen Wulfhorst and Paul Thomasch)