steviestephanie dekker reports. >> reporter: you can't see the bloated drowned bodies of hundreds of people trapped inside. the italian navy has released these images. they won't release the footage of the many dead, but the investigation into what happened on april 18th. >> we found many bodies. it's impossible to say how many of the majority are in the bottom part of the boat, but it doesn't up to what the survivor have told us, that there were around 800 people on the boat. >> only 28 people have survived the accident. the boat collided with the merchant ship coming to their rescue. and in panic the boat capsized. the a robot has been gathering vital information around the deck that lies beneath the surface. some of the navy ships involved in that search are now return to go port. investigators will be scrutinizing the footage of that wreck. one of the key questions is whether some of the migrants interest were locked inside giving them no chance of surviving once the ship started going out. >> the italian prime minister matteo renzi said that try will do everything they can to he