More than 40 years have passed since William Barnes shot rookie Police Officer William Barclay. It was an act that dramatically altered both of their lives - sentencing one to a life of partial paralysis and the other to 20 years in prison - and the effects of those bullets are still being felt.

Barclay died in a Middletown hospital in August at age 67, and the Bucks County coroner ruled his death a homicide from that long-ago shooting. Barnes, 71, then living in a halfway house, was charged with murder. A preliminary hearing to determine whether the case should go to trial is scheduled for tomorrow at the Criminal Justice Center.

The case has drawn national attention: The Washington Post and Toledo Blade weighed in with editorials advocating Barnes' release. Lancaster's Intelligencer Journal asked readers for their opinions during its weekly phone poll: 80 percent of respondents said Barnes should not be tried for murder.

Legal experts have pondered how prosecutors will prove beyond a reasonable doubt that the urinary-tract infection that killed Barclay was directly related to the shooting.

"Because of the factual issues as well as the legal ones, it is fascinating," lawyer Bernard Siegel said. "It encompasses something that rarely occurs, at least with this kind of time consideration."

Upgrading a charge to murder after a victim dies isn't unusual: After Kevin Johnson, 22, died in November 2006, Philadelphia District Attorney Lynne M. Abraham's office filed murder charges against two of the men found guilty of shooting him in 2003 during a West Philadelphia robbery. A court date for the pair, already serving time for aggravated assault and other charges, is set for January.

In April 2005, after 82-year-old Laura Chelinski of Northeast Philadelphia died two weeks after being pushed to the ground during a purse-snatching, suspect William Clegg was charged with murder. He had originally been charged with aggravated assault and robbery.

The challenge for the prosecutor is proving that the defendant's actions led to the victim's death. In the Chelinski case, a judge eventually dismissed the homicide charge because she said there was insufficient evidence to conclude that Clegg's act led to the woman's death.

In the Barnes case, that challenge is heightened by the passage of more than four decades between deed and death.

In November 1966, Barclay responded to a report of a burglar in East Oak Lane. He encountered Barnes, who says he was drunk, in a beauty parlor. Barnes fired twice, striking Barclay in the thigh and shoulder.

The second bullet lodged an inch from Barclay's spine, leaving him partially paralyzed.

Barclay regained some mobility after the shooting - walking with assistance, riding a stationary bike, and driving himself to work - but reinjured his spine in two car accidents and lost the use of one arm after a fall from his wheelchair.

Through a spokeswoman, Abraham declined to comment, but she has previously said prosecutors could prove an "unbroken chain" of events between the shooting and Barclay's death.

If the case goes to trial, it would be a long and expensive one, said Jules Epstein, a Center City lawyer and Widener University law professor.

"We could end up with a battle of experts. This is a medical-intensive case because you need the experts to really say if there is fair causation here," Epstein said. "Then we have the question: Can we do better things with our criminal-justice resources given a 40-year gap? That's a policy call."

Noted Center City defense lawyer Neil Jokelson said the case would also be difficult for the families involved.

"The passage of time not only leaves the perpetrator in limbo. It leaves society in limbo and the victim's family in limbo," he said.

"For better or worse, there's a reasonable argument that closure after a certain period of time by barring the bringing of a murder charge can be helpful to those interests. . . . Society's concern for the heinousness of the crime may be satisfied by the initial charges."

Members of Barclay's family have said they support the prosecution.

Barclay, they said, was in constant pain until his death.

Bobby Hoof, Barnes' court-appointed lawyer, said Barnes believed he had already paid for causing that pain.

"He feels that he did every day of a 20-year sentence," Hoof said. "He feels like he didn't kill this guy."

Authorities note that Barnes did 20 years only because he violated parole after being released after 15 years. During his original jury trial in February 1968, Barnes received the maximum 15-year sentence after being found guilty of multiple charges, including assault and battery with intent to kill. The latter charge is equivalent to attempted murder and allows prosecutors to press their theory that Barnes willfully killed Barclay.

The fact that Barnes has already been found guilty of attempted murder helps the district attorney's case, experts say.

"That removes one obstacle, that there has been no prior jury finding that would be inconsistent with the current prosecution theory," Epstein said.

Barnes, who spent more than 40 years of his life behind bars, was living in a halfway house and working at a grocery store in Roxborough when he was arrested in August.

He had become a frequent speaker at Eastern State Penitentiary, where he was once a prisoner and where he told tour groups of his poor choices and misspent life.

"He turned his whole life around," Hoof said.

Now he's back in jail, held in the medical unit of Graterford Prison because of his age and poor health.

At a September bail hearing, Assistant District Attorney Edward Cameron said that during his decades in prison, Barnes had escaped three times and stabbed another inmate.

Barnes, who has arthritis and uses a cane, has told his guards that escape wouldn't be an issue this time.

"He's had two heart attacks, and the third one is right around the corner," Hoof said. "We hope he can live long enough so we can pick a jury."

Contact Natalie Pompilio at 215-854-2771.