Among the 104 survivors, 53 have filed a criminal complaint
Among the 104 survivors, 53 have filed a criminal complaint AFP

A year after one of the Mediterranean's worst migrant shipwrecks killed more than 600 people, lawyers for survivors pursuing a criminal case against the Greek coastguard gave fresh details on the case Thursday.

The rusty and overloaded trawler Adriana sank on the night of June 13-14 last year. It was carrying more than 750 people, according to the United Nations, but only 82 bodies were found.

Lawyers representing dozens of survivors held a news conference after a court in Kalamata last month dropped charges against nine Egyptian men accused of being part of the criminal gang operating the trawler.

Among the 104 survivors, 53 have filed a group criminal complaint, alleging the coastguard took hours to mount a response despite warnings from EU border agency Frontex and the NGO Alarm Phone.

"This was a crime committed over a 15-hour period," Eleni Spathana, a lawyer with the Refugee Support Aegean (RSA) group, told journalists.

The case is still under preliminary investigation by the naval court of Piraeus, but the survivors' lawyers say they have found many irregularities in the Greek coastguard's actions before and after the incident.

The boat was sailing from Tobruk, Libya to Italy. In addition to Syrians and Palestinians, it was carrying nearly 350 Pakistanis, according to the Pakistani government.

Survivors said the coastguard was towing the vessel when it capsized and sank 47 nautical miles off the coast of Pylos.

The coastguard has insisted it communicated with people on board who "refused any help", rendering any rescue operation in high seas risky.

But on Thursday Maria Papamina, legal coordinator for the Greek Council for Refugees, said the coastguard chose to dispatch a patrol boat from Crete -- and not a larger rescue tugboat stationed closer by at the Peloponnese port of Gythio.

The patrol boat's voyage data recorder was damaged and was only repaired two months after the accident, Papamina added. Nor was there any video footage from the patrol boat.

"There are reasonable concerns of an attempted cover-up," she said.

Spathana of the RSA added: "There was clearly no intent to rescue before the boat sank. Not only is this terrifying, it is criminally liable."

Eighteen of the victims remain unburied, including eight still to be identified.

The independent Greek ombudsman's office has launched a disciplinary investigation into the case, after the coastguard saw no grounds to do so, the lawyers said Thursday.

On Friday, victims' relatives in Pakistan plan to gather in the city of Lala Musa to protest the lack of response from the Greek authorities to the tragedy, organisers in Athens said.