He had an "extensive and violent criminal history" and was considered armed and dangerous, according to police.

CNN: STORY HIGHLIGHTS

Guerrero has seen a growing movement of self-defence groups in response to violent criminal gangs and the failure of police to guarantee security.

BBC: Mexico vigilantes detain police in Guerrero

They had learned that Jenkins hired a two-bit gumshoe named Thomas ("Papa Bear") Miller--a New Orleans operative with a long, sometimes violent criminal record.

CNN: No Saints In New Orleans