Several prominent artists and cultural figures have signed a petition backing release of former Black Liberation Army member Herman Bell, who spent nearly 50 years behind bars for the murder of two New York City police officers in 1971.

Forty-seven years ago, Bell, Anthony Bottom, and Albert Washington were convicted of luring officers Joseph A. Piagentini and Waverly M. Jones to a housing project in Harlem and fatally shooting the officers. Each received a sentence of 25 years to life in prison.

Two weeks ago, Bell, now 70-years-old, was freed by a three-member panel of the New York state parole board after seven previous hearings had denied his parole.

Shortly after the decision to release Bell, an online petition supporting the parole began to circulate.  It now has over 800 signatories. Artists Glenn Ligon, Juliana Huxtable, Hannah Black, Ryan McNamara, John Miller, as well as MoMA curator Thomas Lax, are among those who have signed the petition, which commends the parole board’s “humane decision to release Bell,” calling the move “positive step forward… in the much-needed reform of the criminal justice system.”

The board’s decision has reignited a heated debate over criminal justice that has even split the relatives of the victims. While Piagentini’s widow Diane has vehemently argued against Bell’s release, Jones’s children have previously said they would support his parole. And, as the petition points out, Waverly Jones, Jr., the son of the slain officer, wrote a letter to the parole board expressing support for Bell’s release. “Keeping Mr. Bell in jail after all of these years would serve no purpose other than vengeance, something that we as a family do not need or want,” Jones, Jr. wrote.

City officials and police groups have taken more hard-line positions. Speaking to the New York Times, Patrick J. Lynch, head of the Patrolmen’s Benevolent Association, said “[Bell’s] release on parole is a painful affront to the families of every police officer who has sacrificed his or her life in the line of duty.”

Meanwhile, New York Mayor Bill de Blasio called the decision “tragic and incomprehensible” in a letter urging the board to overturn the parole. “Murdering a police officer in cold blood is a crime beyond the frontiers of rehabilitation or redemption,” he wrote.