The multiple layers worn by migrants who make the treacherous Mediterranean crossing are meant to keep them warm but are often the cause of fatal hypothermia, according to a pathologist who has examined their corpses.

“They normally wear a lot of clothes on top of each other and think this keeps them warm, but in reality it is worse than just wearing one layer,” forensic pathologist David Grima told The Sunday Times of Malta.

“If the clothes get wet, which they always do, it is almost impossible to keep warm,” he added.

Dr Grima, who heads the mortuary at Mater Dei Hospital, has been tasked with carrying out autopsies on all the dead migrants brought to Malta by search and rescue operations conducted between the Italian and Maltese authorities. He recently performed post-mortem examinations on the 24 corpses brought to Malta after some 800 migrants drowned when their overcrowded boat capsized off Libya last month.

Dr Grima said signs of hypothermia were listed in a large number of the migrant cases he had dealt with over the years.

If the clothes get wet, which they always do, it is almost impossible to keep warm

And, while he was reluctant to comment on whether any of the 24 brought here last month had suffered the same fate, he said he would “not be surprised” if this was the case.

“In this sort of situation you should ideally be wearing something waterproof. The reality is that these people will just pile on everything they have to make the trip. The same is true of the last group brought here,” he said.

Dr Grima said that once the layers of clothes were wet, they posed a second risk – weight.

“If you find yourself in the water, wearing three or four layers of clothes, even the most experienced swimmer will find it difficult to keep his head above water,” he said.

Meanwhile, Dr Grima said that work was under way to try to prove the identity of two of the 24 migrant corpses, after he found two Eritrean identification documents among the migrants’ personal belongings.

The Italian Navy is believed to have located the large wooden vessel that capsized in the April tragedy.

It was found using a remotely operated camera on Thursday evening, and the Italian magistrate investigating the case is expected to order the recovery of the wreck.

Survivors reported that hundreds of migrants had been unable to get off the boat when it overturned, as the smugglers had locked them in a cabin below deck.