On the night of June 28, 1993, Eileen Sarmenta and Allan Gomez, both students at the University of the Philippines Los Baños (UPLB), were abducted outside the campus by men working for Antonio Sanchez, then mayor of Calauan, Laguna, and forced into a white vehicle. The pair were taken to Erais Farm in Barangay Curba, reportedly owned by Sanchez. Sarmenta was brought to Sanchez's room while Gomez was beaten by members of Sanchez's staff, including Luis Corcolon, Rogelio "Boy" Corcolon, Zoilo Ama, and George Medialdea. The group later moved Sarmenta and Gomez to a Toyota Tamaraw FX vehicle. Gomez was struck with a rifle butt by Jose "Pepito" Kawit and was later shot. Sarmenta was removed from a resthouse in distress, and Sanchez allegedly handed her over to his men after assaulting her. She was then gang-raped in a sugarcane field in Barangay Mabacan before being shot in the face by Corcolon, according to trial testimony including that of witness Aurelio Centeno.
On June 29, 1993, Sarmenta's mother, Clara Sarmenta, was contacted and led to the site where her daughter's body was found inside the van. A PNP Crime Laboratory examination found Sarmenta had been raped before being killed. Gomez's body was found separately in a grassy area in Calauan, with two gunshot wounds. Investigators recovered the Tamaraw FX vehicle used in the abduction, which had reportedly been cleaned at the Calauan municipal hall, as well as a spent cartridge near Gomez's body. Two suspects surrendered to police and implicated Sanchez as the mastermind. Sanchez himself accused Teofilo "Kit" Alqueza, son of Gen. Dictador Alqueza, of masterminding the killing of Gomez, but prosecutors did not charge Alqueza.
Sanchez was arrested on August 13, 1993, and the case against him and six henchmen — Medialdea, Luis Corcolon, Rogelio Corcolon, Ama, Kawit, and Baldwin Brion — was formally read on September 12, 1993. On March 14, 1995, Judge Harriet Demetriou of the Pasig Regional Trial Court found Sanchez and several henchmen guilty of rape and murder, sentencing Sanchez to seven terms of reclusion perpetua and ordering damages to the victims' families. The Philippine Supreme Court affirmed the conviction on January 25, 1999.
In August 2019, a Bureau of Corrections document signed by then-director Nicanor Faeldon indicated Sanchez could be released under a retroactively applied good conduct time allowance law, prompting public outrage, a Senate inquiry, and Faeldon's dismissal by President Rodrigo Duterte on September 4, 2019. During the Senate probe, Faeldon confirmed that three convicted men — Medialdea, Rogelio Corcolon, and Ama — had already died in prison. Sanchez died in prison at New Bilibid Prison Hospital on March 27, 2021, at age 74; his cause of death was not specified.