The Donegal man detained in Israel after its commandos shot dead nine people on a flotilla of ships heading for Gaza has told the UN that he received a “serious threat” from an official close to the Israeli Prime Minister.

Fiachra O Luain from Carndonagh was second mate on the Challenger 1 and watched in horror as Israeli forces descended on the Mavi Marmara and opened fire.

The 28-year-old, who went to secondary school in Derry, said he had yet to decide whether he would return on the next aid convoy in October.

This week Mr O Luain submitted his statement of evidence to the United Nations Secretary General's Panel Of Inquiry.

In his statement, he reveals how before the raid he alerted Senator John Kerry’s office in the US and the Irish Department for Foreign Affairs to a “serious threat” he received in an email from an official close to Binyamin Netanyahu — the same official with whom he had celebrated the Passover.

Their relationship deteriorated when the official learned Mr O Luain was on the flotilla.

In his evidence he said: “He wrote: ‘Details have been sent to the Foreign Ministry... May you and your boat sink to the depths of the sea, may you know the punishment meted out to the enemies of God’s Chosen People’. Knowing how close this man was to the Israeli Prime Minister, I realised how serious this threat was.”