Black activist and author Mumia Abu-Jamal has petitioned the United Nations Working Group on Arbitrary Detention, arguing that he has been wrongfully imprisoned for more than four decades and seeking international intervention after exhausting legal appeals in the United States.

Abu-Jamal, 72, lodged the petition with the UN Human Rights Council body in Geneva as he approaches the 45th anniversary of his imprisonment in December.

He is serving a life sentence without parole at Pennsylvania’s Mahanoy correctional institution after being convicted in 1982 of the murder of Philadelphia police officer Daniel Faulkner, a charge he has consistently denied.

According to the petition, Abu-Jamal’s legal team alleges multiple violations of international law, including racial discrimination during jury selection, judicial bias and concerns over the credibility of key prosecution witnesses.

The filing also argues that his sentence of life without parole amounts to arbitrary detention under international standards.

Speaking to The Guardian by telephone from prison, Abu-Jamal said he remained hopeful despite the long legal battle, saying he placed his faith in people rather than the courts.

His lawyers believe a favourable opinion from the UN could strengthen efforts to seek a retrial or a commutation of his sentence, although the working group has no authority to enforce its decisions in the United States.

A former member of the Black Panther Party and an award-winning journalist, Abu-Jamal spent 28 years on death row before his death sentence was overturned in 2011 and replaced with life imprisonment without the possibility of parole.

Now the author of numerous books, Abu-Jamal said imprisonment has taken a heavy toll on his health and family life, but he continues to write and pursue academic work despite deteriorating eyesight and other medical issues.