NEW ORLEANS (AP) — Two former Black Panthers convicted of killing a prison guard in 1972 should be freed after a federal magistrate found a previous attorney made mistakes during a trial, their current lawyers said Wednesday.

Magistrate Judge Christine Nolan wrote that Albert Woodfox’s conviction should be overturned because his former attorney should have objected to testimony from witnesses who had died after his original trial and to letting a prosecutor testify about the chief prosecution witness’s credibility.

The attorney’s omission denied Wilcox a fair second trial in 1998, Nolan wrote in a recommendation Tuesday to U.S. District Judge James Brady, who will rule later.

Woodfox, 61, and Herman Wallace, 66, spent 36 years in solitary confinement after being convicted in the stabbing death of guard Brent Miller on April 17, 1972. They said they were targeted because they helped establish a prison chapter of the Black Panther Party.