Gregorio, a reporter and columnist for the weekly Dyaryo Banat, in La Paz, a town in the central Tarlac Province, was talking to a colleague on a cell phone in front of his house when an unidentified gunman shot him in the head three times at close range. According to news reports, the gunman was likely a professional killer who fled the scene on foot. Gregorio was rushed to La Paz District Hospital before being transferred to Ramos General Hospital, where he was pronounced dead on arrival.
Local journalists believe that Gregorio, 55, was killed for his journalistic work. Before joining the newspaper, Gregorio served for nine years as chief of Caramutan, a barangay, or village, in La Paz. During his three years as a columnist for Dyaryo Banat, Gregorio wrote many critical articles about officials in La Paz, including Mayor Dionisio Manuel. Shortly before Gregorio's death, the journalist had accused Manuel of building a cemetery without following local regulations. In interviews with local newspapers, Manuel has denied having anything to do with Gregorio's death.
While police have formed a special task force to solve Gregorio's murder, and Tarlac governor Jose Yap Sr. has publicly urged police to find the killer and prosecute him, no arrests have been made.