The Tunisian man, who captained a boat that capsized off Libya with the loss of more than 750 lives, has appeared in court on the Italian Island of Sicily.
Prosecutors want to charge 27-year-old Mohammed Ali Malek, with homicide and people-trafficking.
Mr Malek’s lawyer said his client was keen to tell his story to prove his innocence to the court in Catania.
One of the 28 survivors had given nearly five hours of testimony, with three others due to speak later.
Prosecutors say survivors identified Mr Malek as the captain of the boat who accidentally rammed the overloaded fishing boat into a merchant ship that had come to rescue it, last Sunday.
The boat capsized with hundreds of migrants allegedly locked in its lower decks and unable to get out.
The death toll is believed to be the highest from a single such incident.
Migrants have continued to seek entry into Europe through the Mediterranean sea, ignoring the risk, since several deaths have been recorded along the route.