It's been 28 years since Mumia Abu-Jamal was convicted of murder and sentenced to die for the shooting death of Police Officer Daniel Faulkner.

But on Tuesday, his case will be back in court for another appellate hearing, and lawyers say a final resolution remains years away.

The latest twist came Friday, when Abu-Jamal's lead attorney, Robert R. Bryan, withdrew from the case, citing "threats" by Abu-Jamal supporters to "embarrass me." Bryan had represented Abu-Jamal for seven years.

Associate counsel Judith L. Ritter, a professor at Widener Law, will now argue the appeal before the U.S. Court of Appeals for the Third Circuit. Which attorney would speak in court had been a matter of dispute among Abu-Jamal supporters, Bryan said.

Abu-Jamal remains on death row at the state prison in Waynesburg in southwest Pennsylvania. His legal team wants to get Abu-Jamal a new death-penalty hearing and will argue that confusing legal instructions to the 1982 jury encouraged execution rather than a life sentence.

The long-running legal review is typical for capital cases in Pennsylvania, where 220 people are on death row but the last execution came in 1999 - only after the inmate, the infamous killer Gary Heidnik, withdrew his appeal.

What is unusual about Abu-Jamal's case is the publicity that attends each decision and hearing, not the length of the litigation, lawyers say.

"They are all like this," said Hugh J. Burns Jr., chief of the appeals unit in the Philadelphia District Attorney's Office. "I suppose it's possible to devise a scenario under which it ends, but there are so many contingencies it is very difficult to figure out how that might work."

Even if prosecutors prevail after Tuesday's arguments, other legal issues will keep Abu-Jamal before the courts, Burns said.

Abu-Jamal, now 56, was convicted of Faulkner's 1981 shooting in 1982, sentenced to death, and officially placed on death row in 1983. He has always maintained his innocence, and his case has become a rallying point among death-penalty opponents and the radical group MOVE.

He is now the second-longest-serving Pennsylvania inmate sentenced to execution, according to state records.

The top spot is held by a Bucks County man, Alfred J. Albrecht, 67, convicted in 1981 of the arson killings of his wife, mother, and daughter.

Albrecht's case has also been on appeal for decades, most recently on the same issue that the Third Circuit court will consider Tuesday for Abu-Jamal: the wording on the jury's verdict sheet, the paper record of the decision passed to the judge.

Lengthy appeals periods in capital cases are common in most states. "This is the tension in our system," said Anne Bowen Poulin, a Villanova law professor who oversaw a 2007 study of how the Pennsylvania courts handle death cases. "The system has procedures in place to try and make sure that mistakes aren't made, and that tension means that people are not executed quickly."

Pennsylvania's uniqueness is that it continues putting inmates on death row but almost never carries out the penalty, said Richard Dieter, executive director of the Death Penalty Information Center in Washington.

"Pennsylvania really stands out" because it has the fourth-largest death-row population in the nation, Dieter said, yet its "ambivalence" toward state-sponsored executions means it "has made the death penalty more scrutinized."

Dieter compared Pennsylvania with Texas, which has 337 people on death row and has executed 464 people since 1976, when the Supreme Court reinstated the death penalty. Pennsylvania has staged three executions in the same period.

Abu-Jamal's attorney will argue Tuesday that at the 1982 trial, awkwardly written legalese encouraged jurors to impose the death penalty rather than consider life in prison without parole.

At the root of Abu-Jamal's argument is that jurors may have been confused by how the word unanimously was used on the verdict sheet.

In capital cases, jurors first have to check a box to say whether they reached a unanimous guilty verdict, then have to declare whether they found any "mitigating" circumstances that might favor a life sentence rather than the death penalty.

Jurors do not have to unanimously agree on which mitigating circumstance to consider, but Abu-Jamal's attorneys say the written instructions in 1982 did not make that clear.

The form then used "plainly requires the jury to find each mitigating circumstance unanimously," Abu-Jamal's attorneys contend.

The Third Circuit court agreed with Abu-Jamal in 2008, but Philadelphia prosecutors appealed to the U.S. Supreme Court, which this year tossed the case back for reconsideration.

Burns says the Supreme Court decision means the Third Circuit court must now allow the death sentence to stand.

Bryan, of San Francisco, contends the reverse. Indeed, the verdict sheet in capital cases was revised in 1989 by the Pennsylvania Supreme Court.

A decision is not likely until some months after Tuesday's hearing.

Contact staff writer Nathan Gorenstein at 215-854-2797 or ngorenstein@phillynews.com.