Humberto Zorrillo (b. 11 Nov 1954; d. 19 Dec 1991) – also known as El Papa de Mexicali ("The Pope of Mexicali") – was a former resident of the Saints & Sinners barrio in Mexicali, Baja California, and the half-brother of Calexico Moore. Zorrillo left the barrio to become a drug dealer, and eventually worked his way up to take over the Mexican black ice trade. He operated a clandestine underground laboratory on his 6,000-acre bull ranch in southwest Mexicali.
In December of 1991, he was lured to the Hideaway motel in Los Angeles by his half-brother, who was by then a Narcotics detective with the Los Angeles Police Department. Zorrillo was ambushed by Moore, who knocked him unconscious with a blow to the head and placed his body in the bathroom of Room 7 of the motel. Moore shot Zorrillo in the face with a double-barrelled shotgun, then proceeded to set the scene to create the illusion that Moore had committed suicide. This included removing all fingerprints from the room except those of Zorillo.
Moore had previously switched the fingerprint card in his personnel file with a card bearing Zorrillo's prints, intending for the LAPD to assume that Zorrillo was actually Moore so that Moore could leave the United States and, at least temporarily, take over Zorrillo's place in Mexicali. Zorrillo's body was found by the wife of the motel's owner on 25 December 1991 with a note, written by Moore, reading "I found out who I was." The case was assigned to LAPD Robbery-Homicide detective Frankie Sheehan and IAD detective John Chastain. IAD had an ongoing investigation of Moore, leading the investigators to assume incorrectly that that body in the room was Moore. Harry Bosch investigated the case on a freelance basis, determining the real identity of the victim and his killer.