An Albanian asylum-seeker died of compression of the neck caused by suspension by ligature, an inquest into his death on the Bibby Stockholm barge has heard.
Leonard Farruku, 27, died aboard the vessel, based at Portland Port off Dorset and used to house migrants, last Tuesday.
He had claimed migrants there were being treated “like animals”, his sister has said.
Home Secretary James Cleverly said the sudden death would be fully investigated.
A preliminary inquest hearing is normally held to formally establish the deceased’s identity, location of death and potentially a cause of death before being adjourned for a full hearing at a later date.
The inquest, at Dorset Coroner’s Court in Bournemouth, is being overseen by Rachael Griffin, senior coroner for Dorset.
Mr Farruku paid 4,000 euros to cross the English Channel in a small boat to arrive in the UK, according to The Daily Telegraph.
His sister, Jola Dushku, 33, who lives in Lombardy in Italy, said her brother had expressed concerns to her about how migrants on the Bibby Stockholm were being treated.
She told The Telegraph: “When I spoke with him last time, he told me that the conditions in that boat were not bad but they were treated by the guards like animals…
“According to our relatives who are in touch with the police, Leonard that night at 11pm in the evening had some problems and was calmed down by the security guard. At 3am he was found dead. We do not have more details about how he died.”
Asylum-seekers were first moved on board in August but were taken off days later after the discovery of Legionella – the bacteria that can cause the potentially fatal Legionnaires’ disease – in the water supply.
Migrants were taken back to the barge some two months later and civil servants reported last month that there were around 200 people on board.
News of the death drew criticism from charities who called for an independent review and an end to the use of such facilities for asylum accommodation.