Captain Gustavo Grena (d. 29 Dec 1992) was the director of investigations with the Baja California State Judicial Police in Mexicali, and the supervisor of Lt. Carlos Aguila. On 27 December 1992, he received a call from LAPD detective Harry Bosch regarding the disappearance of Fernal Gutierrez-Llosa. He was killed by Osvaldo Arpis Rafaelillo on 29 December 1992 just prior to an incursion on the ranch of Humberto Zorrillo.