Costa Concordia's Captain Francesco Schettino allegedly changed the ship's speed to finish dinner in peace with his guest, the Moldovan ex-dancer Domnica Cemortan, shortly before it ran aground on rocks off the Italian coast, prosecutors have said.
Witnesses claimed to have spotted 52-year-old Schettino accompanied by a blonde girl, later identified as Cemortan, in the luxury restaurant on the top deck of the liner at the time of impact.
"The captain was accompanied by two women, a blonde and a dark-haired one," said Marco Monda, a passenger on the cruise ship. "He was showing off Giglio island. He was with us at the time of the accident. Then he ran away, as everyone else. It was awful, there was nobody from the crew to help us evacuate."
Prosecutors said the captain "slowed down the ship so that he could finish dinner in peace", the Daily Telegraph reported.
Schettino then ordered the ship's speed to be increased "despite the proximity of obstacles, the presence of shallow water, the conditions under which the ship had to manoeuvre and the night-time darkness," prosecutors charged.
The death toll from the disaster stands at 25 after divers found eight more bodies inside the liner's hull.
Among them was a five-year-old child, Dayana Arlotti, the youngest passenger on board.
Along with Schettino and the first officer, Ciro Ambrosio, four ship's officers are under investigation.
They have been accused of acting with "imprudence, negligence and malpractice" and waited too long to give the order to abandon ship.