Sergio Triminio received a message on Facebook in September last year with a plea for help.
The brother of missing Falls Church, Virginia., teenager Edvin Mendez, who Triminio knew, was looking for help in finding him. Triminio, 14, agreed to meet and later told the brother what he knew: Mendez, 17, was kidnapped and killed by the MS-13 gang. The killers suspected that Mendez was a spy for the gang’s rival.