The key to the night's tragic events lies in the actions of the captain, now under house arrest and facing charges of multiple manslaughter, causing a shipwreck and abandoning ship.
At around 9.05pm, Captain Francesco Schettino, 52, was seen leaving the Concordia Club on Deck 11, in the company of Domnica Cemortan, an off-duty Moldovan member of the crew, and another officer.
A witness said the party had drunk at least a decanter of red wine, raising questions over Mr Schettino's insistence that he drank no alcohol.
Prosecutors have established that the captain was at the controls of the Costa Concordia 37 minutes later, when he steered the huge cruise ship onto rocks off the island of Giglio as he was allegedly trying to perform an 'inchino' -- or sail-past salute. This risky manoeuvre appears to have been established practice for some Costa captains.
Also on the bridge was Ms Cemortan, who investigators want to interview to shed light on what happened.
By 9.45pm the ship was listing by seven degrees and some passengers, beginning to realise that something was badly wrong, made phone calls to relatives, leading to the coastguard in Livorno being notified that the cruise liner was in trouble.
Mr Schettino only called his employers at 10.05pm -- 23 minutes after the collision -- reporting a problem with the ship. However, when the Livorno harbour master's office radioed a minute later the ship said it had suffered a "blackout".
Twenty minutes later Livorno radioed again and Mr Schettino admitted water was entering the hull -- but said there was no emergency. By 10.30pm the ship was listing by 20 degrees and he finally issued a May Day signal, waiting a further 20 minutes -- at 10.58pm -- before ordering the ship to be abandoned.
Mr Schettino should then have waited for the ship's passengers to be evacuated before leaving himself. However, witnesses saw him wrapped in a blanket getting on a lifeboat just over an hour after ordering the evacuation.
The captain told magistrates it was only because he had "tripped" and fallen into the rescue craft.
At 5am Mr Schettino called his mother Rosa, 80, telling her: "Mamma, there's been a tragedy. But don't worry, I tried to save the passengers."