A federal appeals court ruled Thursday to overturn the death sentence of black activist Mumia Abu-Jamal, concluding that jury instructions were flawed.

The judges said that Abu Jamal, whose given name is Wesley Cook, cannot be executed for murdering a Philadelphia police officer in 1981 without a new sentencing hearing.

In its decision Thursday in Philadelphia, the 3rd U.S. Circuit Court of Appeals upheld Abu-Jamal's first-degree-murder conviction for killing Officer Daniel Faulkner, 25, after Faulkner stopped Abu-Jamal's brother in an overnight traffic stop.

The judges rejected his appeal for a new trial and a chance to prove his innocence.

The Third Circuit upheld a 2001 decision by U.S. District Judge William H. Yohn Jr., who threw out the death sentence.

Abu-Jamal, 53, is a former member of the Black Panther Party. His case has made national attention as many view his conviction as an act of blatant racism. Several protestors nationwide have spent years rallying for his release as they chant "Free Mumia, Free Mumia".