A French prisoner who killed his cellmate "very probably" ate some of the victim's body parts, a prosecutor in the northern town of Rouen said on Friday.
The victim's body was discovered in a prison cell on Wednesday, with a large wound to the chest. The alleged killer, who shared the cell, told investigators he had removed and eaten his victim's heart.
Investigators initially discounted the possibility of cannibalism after the victim's heart was "found intact in its usual place and in its membrane which was also intact," Rouen state prosecutor Joseph Schmit said in a statement.
However an autopsy revealed that pieces of muscle from the victim's rib area and part of his lung were missing.
"The absence of these anatomic elements, which have not been found on the scene of the crime, render the confessions of cannibalism by the presumed perpetrator of the crime very probable," Schmit said.
The case comes less than a year after a court in Germany sentenced Armin Meiwes, the cannibal who killed and ate a willing victim, to life in prison.
The alleged Rouen killer and another cellmate who admitted he had not been asleep at the time of the crime, were in temporary custody and would be placed under formal investigation for premeditated murder, Schmit said.