The mystery of 1,800-year-old remains unearthed in York may have been solved thanks to bite and hammer marks on their decapitated skulls.
Archaeologists have exhumed 80 skeletons from gardens at Driffield Terrace over the past decade.
The results of forensic work on the skeletons suggests they may be part of the world's only well-preserved Roman gladiator cemetery.
Marks on the remains suggest some individuals died in a violent manner.
The research features in a Channel 4 documentary, Gladiators: Back from the Dead.
Kurt Hunter-Mann, a field officer at York Archaeological Trust, said bite marks on one of the skeletons helped steer the team to their preliminary theory.
He said: "One of the most significant items of evidence is a large carnivore bite mark - probably inflicted by a lion, tiger or bear - an injury which must have been sustained in an arena context."
Mr Hunter-Mann said other "important" pieces of evidence included healed and unhealed weapon injuries and possible hammer blows to the head.
He said nearly all the skeletons had features consistent with gladiators, as the majority were male, very robust and mostly above average height.
He also said the team found clues in the arms of the skeletons.
"The arm asymmetry would also be consistent with weapons training that had already started in teenage years, and we know from Roman accounts that some gladiators entered their profession at a very young age."
The skeletons date from the late first century AD to the 4th century AD.
The researchers said all the individuals were buried with some respect and 14 of them were interred together with grave goods to accompany them to the next world.
Interred with one man were what appear to have been the remains of substantial joints of meat from at least four horses, possibly consumed at the funeral, plus some cow and pig remains.
He had been decapitated by several sword blows to the neck.
Mr Hunter-Mann said: "At present our lead theory is that many of these skeletons are those of Roman gladiators.
"So far there are a number of pieces of evidence which point towards that interpretation or are consistent with it.
"But the research is continuing and we must therefore keep an open mind."
Gladiators: Back From The Dead will be shown on Channel 4 on Monday, 14 June at 2100 BST.