The paramedics and rescue workers killed in an Israeli shooting in Gaza last month died mainly from gunshots to the head or chest, while others had shrapnel injuries or other wounds, according to autopsy reports obtained by The New York Times.

Israeli troops had fired on ambulances and a fire truck sent by the Palestine Red Crescent Society and the Civil Defense, according to witness accounts, video and audio of the March 23 attack.

Israel acknowledged carrying out the attack, which killed 15 men: 14 rescue workers and a United Nations employee who drove by after the others were shot. Israeli soldiers buried most of the bodies in a mass grave, crushed the ambulances, fire truck and a U.N. vehicle, and buried those as well.

The Israeli military has offered shifting explanations for why its troops fired on the emergency vehicles and said, without providing evidence, that some of the dead men had been Hamas operatives. Israel’s military said it was investigating the killing.

The episode drew international condemnation, and experts described it as a war crime.

The autopsies were carried out between April 1 and April 5, according to the reports, after a team of aid workers recovered the men’s bodies from southern Gaza. The Times reviewed autopsy results for all the men except the U.N. employee. They were performed by Dr. Ahmad Dhair, the head of the Gazan health ministry’s forensic medicine unit.

Dr. Arne Stray-Pedersen, a forensic pathologist at Oslo University Hospital in Norway, who had been in Gaza earlier in March to train doctors in forensic medicine, reviewed photos of the autopsies and consulted with Dr. Dhair to write a summary report.