An extremist who fought with the Taliban has been accused of killing a Corsican nationalist serving time for a politically motivated murder.
Both were in jail in France at the time of the second man’s death.
Yvan Colonna died in hospital on Monday after being attacked earlier this month in a prison gym in the southern French city of Arles.
The assailant, identified as Franck Elong Abe, had fought with the Taliban and said he became angry when Colonna blasphemed.
A bag was put over his head and an attempt was made to strangle him.
Abe was detained in Afghanistan in 2012 by US soldiers before being handed over to France in 2014.
He has remained in prison with a further sentence imposed after an apparent escape attempt.
The attack, on March 2, sparked rioting in Corsica where Colonna, who was 61, was seen by some as an independence hero for murdering the island’s top official, Claude Erignac, in 1998.
Colonna went on the run and was arrested five years later.
He was found to be living in a stone shepherd’s hut herding goats in the Corsican mountains.
Colonna, who had always said he was innocent, was sentenced to life in prison.
French officials had refused nationalist demands for his freedom or a transfer to Corsica. But the French judiciary last week suspended his prison sentence for medical reasons.
The government also opened a discussion about seeking autonomy for the island to calm tension.
French President Emmanuel Macron said the issue should not be a “taboo debate” and that talks would begin in April.
The National Liberation Front of Corsica (FLNC) carried out deadly attacks for decades before laying down its arms in 2014.
It sounded a warning earlier this month that it could resume its fight if Paris remains in a state of “contemptuous denial”.
Corsica, the birthplace of Napoleon Bonaparte, is known for its pristine beaches and beautiful landscapes.
It has been French since the 18th century, but many islanders have demanded increased control over fiscal policy and the expanded use of the Corsican language.
The debate has intensified at a sensitive moment, with Paris preparing for presidential elections in April and the political right warning Mr Macron not to give up an inch of the island’s French identity.