A group representing relatives of hostages taken in the Oct. 7 attack on Israel said on Thursday that autopsies showed “bullets were found in the bodies” of six captives Israeli troops recovered from an underground tunnel in southern Gaza, raising questions about how they died.

The group, the Hostages Family Forum, said that the autopsy results indicated that the six hostages “were taken alive and executed in the tunnels of Hamas.”

But an Israeli military spokesperson, speaking on condition of anonymity because of the sensitivity of the matter to families, said on Thursday that the autopsies showed “marks suggestive of gunshots” on the bodies and stressed it was too soon to determine whether gunshot wounds were the cause of death.

The autopsy reports have not been made public. The New York Times has not reviewed them and cannot confirm the results.

Four other bodies found in the tunnels near the hostages, believed to belong to Hamas militants, did not display the same marks, the military spokesperson said.

How and when the hostages died has been a matter of contention. Hamas has blamed the deaths on Israeli airstrikes, and the Israeli military has acknowledged some of them likely died while Israel was carrying out military operations in the area where they were found. Some Israel news outlets reported the hostages may have suffocated when the tunnel fill with toxins after an airstrike.