A former Guantanamo Bay detainee released in South America has been misplaced, and a Brazilian airline has issued an alert asking its employees to be on the lookout for him.

Abu Wa’el Dhiab, who was released in Uruguay in December 2014 after twelve years spent in detention, has vanished after purportedly entering Brazil. Uruguayan authorities claim he was authorized to visit the country as a refugee, but Brazil has no record of his arrival.