PHILADELPHIA (AP) — Former death-row inmate Mumia Abu-Jamal is in court asking a judge to vacate his previous failed appeals attempts, so he can again appeal his case.

The former Black Panther spent 29 years on death row following his conviction in the 1981 murder of white Philadelphia police Officer Daniel Faulkner. Abu-Jamal's sentence was reduced to life without parole in 2011.

His lawyers are petitioning under the Post-Conviction Relief Act. They'll argue Monday his rights were violated when trying to appeal his case numerous times because of the bias of State Supreme Court Justice Ronald Castille.

Castille is a former Philadelphia District Attorney. As prosecutor, he succeeded in getting the State Supreme Court to uphold Abu-Jamal's conviction.

Abu-Jamal has maintained his innocence and has become a symbol for groups seeking criminal justice reform.