Italian prosecutors are investigating the mystery rounding the deaths of 26 Nigerian women who are mostly teenagers whose bodies were recovered at sea.
There are suspicions that they may have been sexually abused and murdered as they attempted to cross the Mediterranean.
Five migrants are being questioned in the southern port of Salerno.
A Spanish warship, Cantabria, docked there carrying 375 migrants and the dead women, following several rescues.
Twenty-three of the dead women had been on a rubber boat with 64 other people.
According to Italian media, the women’s bodies are being kept in a refrigerated section of the warship. Most of them were aged 14-18.
Most of the 375 survivors brought to Salerno were sub-Saharan Africans, from Nigeria, Senegal, Ghana, The Gambia and Sudan, the daily La Repubblica reports.
Among them were 90 women – eight of them pregnant – and 52 children.
There were also some Libyan men and women on board. Police have detained 7 people for questioning including two men of Libyan and Egyptian origin who are believed to be the captains of the vessel.
People-smuggling gangs charge each migrant about $6,000 (£4,578) to get to Italy, $4,000 of which is for the trans-Saharan journey to Libya, according to the Italian aid group L’Abbraccio.
Many migrants have reported violence, including torture and sexual abuse, by the gangs.
