Despite a judge’s order calling for his return to the United States from El Salvador, a Venezuelan migrant was instead sent back to his home country in a prisoner exchange deal reached last week, an unexpected development that left his lawyers scrambling to locate him.

A former U.S. Navy SEAL was among ten Americans and U.S. permanent residents released from Venezuelan detention on Friday as part of a high-level prisoner exchange. The deal involved the swap of 252 Venezuelan migrants from the United States to a maximum-security prison in El Salvador.

But one of those men is an American-Venezuelan dual citizen who was convicted of murdering three people in Spain in 2016, according to Venezuelan court records and statements from officials in Madrid.