More than 300 migrants heading to the UK last summer were kidnapped, tortured and threatened with forced organ removal.
The young men, all from Iraqi Kurdistan, were captured in Libya by a militia who demanded a ransom of $5,000 (£3,700) from each of their families, and threatened to harvest the captives' kidneys if payment was not made promptly.
At least one hostage is known to have died, and it is unclear how many remain captive.
The militia was supposed to be guiding the migrants through Libya to the Mediterranean coast.
However, a dispute over payment had broken out with the Iraqi Kurd people-smuggler, Noah Aaron, who had organised the migrants' journey.
According to the BBC, some hostages who have since been released, with photo evidence suggesting that forced operations did take place.
The former captives showed evidence of torture, and said they had been kept in cramped conditions, with nearly 180 people sharing a cell.
