Edward Arrango was a detective with the Los Angeles Police Department West Valley Division's homicide unit, and the partner of Dennis Walters. He is a latino in his mid-forties (in 1998) with black hair starting to go gray, a wide body but not a big gut, and a major attitude problem. He wears his gun in a shoulder holster, although most homicide detectives have little need to wear a weapon.
In February of 1998, he and Walters investigated the murders of Gloria Torres and Chan Ho Kang, but they weren't getting anywhere with it and had moved on to other cases. When Terry McCaleb came in to talk to Arrango and Walters about the case, it turned into a "Hard Tango", especially because McCaleb was no longer with the bureau. Arrango took an immediate dislike to McCaleb, and the feeling was mutual.
When the FBI became officially involved in the investigation, Arrango was part of the joint task force because the Torres/Kang killing was linked to the murders of James Cordell and Donald Kenyon. Evidence planted by the real killer led Arrango and others to suspect McCaleb. Arrango was looking forward to arresting McCaleb, making himself a public hero. He was severely disappointed when McCaleb actually found the killer and received an apology from the FBI.