According to current information from public authorities, there was a six-hour gap on Saturday night between the moment the boat from Turkey with some 180 people on board was spotted by EU border agency Frontex and the start of the rescue operation by Italy's coastguard.
By then, the overcrowded boat shattered not far from the shore in a storm, sending the migrants - including many children - into the sea.
The Crotone prefect's office said Thursday it had thus far identified 54 victims of the shipwreck. Those included 48 Afghans, three Pakistanis, and one person each from Syria, the Palestinian Territories and Tunisia.
The latest body, that of a young adult, was found on Thursday, bringing the death toll to 68, the prefect's office said.
For the investigation, police will now have to reconstruct the chronology of the reports received by Italy's coastguard and their subsequent actions.
Following the shipwreck, Frontex said that one of its patrol aircraft had spotted a heavily overloaded boat on Saturday night that had left from Izmir and was heading for Italy.
The agency said it had alerted the Italian authorities, which it said had dispatched two patrol boats that were forced by bad weather to return to port.
The coastguard said Frontex had seen the boat "with only one person visible" and a vessel of Italy's financial police had tried to intercept it.
The disaster has further fueled the debate in Italy over search and rescue measures for saving migrants who run into trouble on the Central Mediterranean route, the world's deadliest.
Rome blames its EU partners for a lack of solidarity in dealing with this thorny issue.
Separately on Friday, the coastguard said it had rescued 211 migrants from a fishing boat in distress during the night in bad weather some 15 kilometers off the island of Lampedusa.
The rescue was "particularly complex due to the adverse weather and sea conditions, the large number of people on board, and the precarious condition of the drifting vessel, which was beginning to take on water," the coastguard said.
According to the Italian interior ministry, as of Thursday 14,432 migrants had landed in Italy since the beginning of the year, compared to 5,474 during the same period last year and 5,305 in 2021.
