A man who killed 13 people in a 1982 shooting rampage in northeastern Pennsylvania can't be executed because he suffers from a major mental illness, a judge ruled Monday.

George Banks, 66, is psychotic and unable to comprehend his sentence or participate in his defense, making him incompetent to be put to death, Judge Michael Conahan said.

Banks, whose victims included five of his own children, "has a hopeless prognosis and will not improve to any acceptable degree," the judge said.

Defense experts testified at a hearing last month that Banks believes his sentence has been vacated by God or Jesus, that he is no longer under the threat of death, and that he is being held in prison as part of a conspiracy to get him to renounce his religious beliefs.

Defense attorney Al Flora said Monday that prosecutors should stop their decades-long pursuit of the death penalty for Banks, saying it is no longer worth the time and expense.

"I think it's about time that this community really gets beyond the George Banks case," Flora said. "The man is dying in isolation. He's severely mentally ill, and I think each day he's tormented by his own mind."

Prosecutors said they have no intention of dropping the case.

Assistant District Attorney Scott Gartley said that even though Banks is mentally ill, he "comprehends the reason for his sentence and its implications" and thus meets the legal standard for execution. He said the district attorney's office will appeal the ruling.

Banks, a former prison guard, picked up a semiautomatic rifle on Sept. 25, 1982, and began shooting at two houses in Wilkes-Barre and nearby Jenkins Township. He killed a total of seven children; his three live-in girlfriends; an ex-girlfriend; her mother; and a bystander in the street.

Banks, who is biracial, has maintained that he shot his children to spare them the racial prejudice he endured in Wilkes-Barre, a city 100 miles north of Philadelphia. Prosecutors noted his history of abusing women and said he had been involved in a nasty custody battle with one of the victims.

The Pennsylvania Supreme Court halted Banks' execution in December 2004 and ordered a hearing to determine Banks' mental competency.

Conahan ruled in early 2006 that Banks couldn't be put to death, but the state Supreme Court ordered a fresh hearing to determine Banks' mental state after finding that the judge improperly barred a prosecution psychiatrist from testifying.