Héctor David Delgado Santiago (23 December 1975 – 15 January 2013), commonly referred to by his alias El Metro 4, was a suspected Mexican drug lord and high-ranking leader of the Gulf Cartel, a criminal group based in Tamaulipas.

After several years, his position in the cartel grew, and he later became the regional leader in Reynosa, Tamaulipas and the right-hand man of the drug lord Mario Ramírez Treviño.

At some point in his career, El Metro 4 worked as the regional boss of the Gulf Cartel in Reynosa, Tamaulipas and as the right-hand man of the current leader Mario Ramírez Treviño.

[2] Between September and October 2012, El Metro 4 was riding a battered old car (to avoid detection by the military) while heading to Río Bravo, Tamaulipas when he was pulled over by the transit police.

[7] Although there is not an official statement from the U.S. and Mexican authorities, several media outlets that cited "extra-official sources" alleged that El Metro 4 was killed in Reynosa, Tamaulipas on early hours of the morning on 15 January 2013.

[8][9] It was later indicated, however, that the man who died in the hospital was another top criminal in the Gulf Cartel, and that El Metro 4 had actually disappeared a few days before and that his body was found dead by the Mexican authorities in Reynosa.

[9][10] If El Metro 4 was betrayed, it remains unclear for whom the assassins were working, whether or not some Gulf Cartel members shifted to Los Zetas, or if it was an internal strife.