Gisela Zambrano Bendong was born on May 21, 1977, in Iligan City, Philippines. She became the first female commercial pilot for Philippines AirAsia, having faced gender-based discrimination early in her career. She met Niño Rey Feniza Boniel, then mayor of Bien Unido, Bohol, at a conference in Tagbilaran. They married in civil rites in 2012 after Gisela became pregnant, and their first child was born that July. In the 2016 elections, Niño Rey moved to a seat on the Bohol Provincial Board while Gisela succeeded him as mayor of Bien Unido; both won. Gisela reportedly faced political attacks tied to her husband and controversies linked to him, and the marriage was reportedly strained by financial disagreements, including her purchase of an expensive watch.
On June 6, 2017, Mayor Boniel traveled from Cebu City to Tagbilaran with her best friend Angela Celeste Gamalinda-Leyson and her then 17-year-old son for a cyberlibel hearing and a follow-up inquiry at the Commission on Audit regarding a municipal deficit. Although the group had planned to return to Cebu that night, municipal officials persuaded Boniel to travel to Bien Unido to sign documents, reportedly related to an annulment and her intended resignation as mayor. When the document holders proved unavailable, the group stayed overnight at the municipally owned Dive Camp Resort.
In the early morning hours of June 7, 2017, several men entered the room shared by Boniel and Leyson. Leyson was restrained and rendered unconscious; she later testified she overheard Boniel pleading with a man she recognized by the nickname "In-In," understood to be her husband. Leyson and the mayor's son were later taken to Tubigon and put on a boat to Cebu, with Boniel's name falsely entered on the manifest to suggest she had also traveled. According to testimony from a cousin of Niño Rey and a municipal driver, Gisela's body was transported by boat and, per one witness account, Niño Rey shot her before her body was weighted with a rock and disposed of at sea between the Olango Island Group and Bohol. Niño Rey, during interrogation, said his cousin was the shooter; the cousin and the driver alleged it was Niño Rey.
Search and retrieval operations for Boniel's body began June 9, 2017, and were called off permanently on July 15, 2017, after failing to locate her remains. A body found on July 1, 2017, in Tabuelan waters was ruled out as Boniel's and identified as belonging to another woman. Her family held memorial services at sea in July and November 2017.
Niño Rey Boniel was charged with parricide, kidnapping, serious illegal detention, and physical injuries, and initially pleaded not guilty to the latter three charges. He resigned his board seat in June 2018. On February 8, 2022, he pleaded guilty to a reduced charge of homicide under a plea bargain and was sentenced to 8–14 years in prison; separate kidnapping and serious illegal detention cases remain pending.