Image caption Supporters had asked Louisiana to release Wallace on humanitarian grounds

A Louisiana man released from prison on Tuesday after 41 years in solitary confinement has died of liver cancer.

Herman Wallace, 71, died on Friday morning, his lawyer told the BBC.

He was freed after a federal judge ruled his 1974 murder conviction violated his right to a fair trial.

Wallace, one of the so-called Angola Three convicted in the murder of a prison guard, was diagnosed with cancer this year. The three had always maintained their innocence.

Image caption Herman Wallace, left, and his legal team were seen following his release from prison

"He passed away early this morning among people who cared for him very much," Wallace's lawyer, George Kendall, told the BBC.

One of the Angola Three, Robert King, was released in 2001. Wallace and another man, Albert Woodfox, remained incarcerated, isolated in tiny jail cells and allowed out to shower or exercise one hour a day.

'You're free'

The men, initially imprisoned for robbery, were the object of a long-running international campaign arguing they were wrongly convicted of the murder because of their association with the militant Black Panther Party.

Analysis In a 6ft-by-9ft cell - just under 3m-by-2m - Wallace stayed in shape by lifting weights that he constructed out of old newspapers. He read material about the Black Panther Party, a 1960s revolutionary group - and anything else he could get his hands on, and kept up with current events. Wallace replied to letters - he got a steady stream of mail - and worked on his appeal. Surviving 41 years in solitary

On Tuesday, Judge Brian Jackson ruled Wallace's conviction was unconstitutional because women were barred from serving on his jury, and ordered him freed.

Louisiana State Penitentiary, where the three men were held, is nicknamed Angola for the plantation that once stood on its site, worked by slaves kidnapped from Africa.

Wallace was in a nursing clinic at Hunt Correctional Center in St Gabriel, Louisiana, on Tuesday morning when he heard the news.

"I said, 'Herman, you are a free man,'" Carine Williams, one of his lawyers, told the BBC.

By many accounts, the evidence against him was weak, says the BBC's Tara McKelvey.

There were no fingerprints at the place where Miller was killed, our correspondent says.

Even Miller's widow, Teenie Verret, said she had doubts about the case against the Angola Three - and hoped they would be treated fairly.

On Friday, Amnesty International said Louisiana prison authorities had put Wallace "through hell".

"No one should have to endure 40-plus years in solitary confinement... It's some small consolation that [Wallace] died a free man after the conviction was finally overturned," said Amnesty International campaigner Tessa Murphy.