Prosecutors in Genoa have placed the captain of the Jolly Nero cargo ship under investigation for alleged manslaughter after the vessel slammed into the dock at the busy port and toppled the control tower into the harbor, killing at least seven people.

Prosecutor Michele de Lecce said Wednesday the harbor pilot on the ship's bridge at the time of the crash was also placed under investigation.

Such investigations are par for the course in Italy.

Transport Minister Maurizio Lupi told Parliament that given the "perfect" weather conditions Tuesday night, possible causes of the crash could include an engine malfunction or problems with the cables between the container ship and the tugs guiding it.

He said investigators were also looking into possible mistakes with the maneuver itself.