A French prisoner reportedly decapitated a fellow inmate by using a broken piece of a porcelain bowl after a row.
The early morning attack took place at the Baumettes prison in Marseille in the south of France, French media reported.
The suspect, 22, is said to have killed his cellmate, 25, in the frenzied attack.
French media reported that the victim had his throat deeply slit and had been "practically decapitated" during the attack on the prison’s arrivals wing.
They had been there for several weeks before the killing.
Prison sources told Le Parisien newspaper: "It had been several days that they had not gotten along - he could no longer stand [him]."
The attacker was reportedly a homeless man who was jailed for six months for possession and transportation of drugs.
He has been taken into custody at a police station.
The victim was in prison on remand while facing drugs charges.
The French Minister of Justice Didier Migaud said: "I confirm to you that a crime was committed, I cannot comment further but I confirm it."
Amra was being taken back to jail from a court in Normandy when a car rammed his prison van at a toll booth on May 14.
Armed men shot at the prison vehicle, killing two officers and injuring three others - marking the country’s first fatal attack on prison staff in more than three decades.
A manhunt was then launched for the 30-year-old drug dealer but it has so far been unsuccessful.
Prosecutors said he was under investigation for a kidnapping and homicide case and was also suspected of ordering the assassination of a Frenchman in Spain in 2023.
He had recently been sentenced to 18 months for burglary.
