Relatives of French sailors who mysteriously drowned off the English coast nearly two decades ago, on Friday urged France's foreign minister to reveal all he knows about the incident.
The sinking of the Bugaled Breizh trawler in 2004 off Cornwall, killing all five aboard, is currently being examined at an inquest at the High Court in London.
"The trial that is being held in London may be the last chance for the victims to get to the truth," lawyers for the relatives said in a letter to France's top diplomat Jean-Yves Le Drian, adding that the families "wouldn't understand if you continue to cover up what you said you knew about this case".
Relatives of the dead men are hoping for confirmation of their belief that the boat was dragged down by a submarine.
Naval exercises involving British and NATO submarines were taking place in the area around the time of the sinking, which happened in about a minute in fair weather conditions.
The letter to Le Drian, seen by AFP, mentions that in 2013 he said: "The English have not said everything."
The minister also comes from Brittany, in northwest France, where the Bugaled Breizh was based.
Judge Nigel Lickley began hearing testimony on Monday and the case is expected to last three weeks.
Lickley said on Thursday that three submarines -- Dutch, German and British -- were operating in the area at the time.
The Dutch submarine had surfaced and was closest to the fishing boat when it sent a distress call. Rescuers have told the court they saw a submarine on the surface as they arrived at the scene.
Martin Brooman, a crew member of a rescue helicopter, said on Friday: "We discussed the fact that it wasn't good to see a submarine in the vicinity of a fishing vessel.
"I can't speculate on what happened on that day but submarines do pose a threat to trawlers."