O'Neil had been lured not to the Punta Pacifico but to another hotel, where he had been beaten so badly that his lungs were punctured, investigators told Donnie.
His brother's body was then wrapped in a hotel curtain, stuffed inside a large bag, ferried across town in a taxi and buried in a yard under freshly poured concrete.
Then came the gunshots late one night inside Brian's bedroom in Silver Spring, Maryland, and the phone ringing 2,000 miles away in Mazatlan. The answer came two weeks later when police arrested four men, one of whom had arranged to meet Brian via a telephone chat line only to rob him, shoot him and leave him to die. It was in Mazatlan that O'Neil met Jorge, a handsome young Mexican with dark hair, green eyes and a tattoo across his tightly muscled chest reading “Warrior of God.” They had dated for a short time before opening a cafe together in 2014. O'Neil had gone on a date the night before with someone he'd met on a gay dating app, Jorge said, and O'Neil wasn't home yet, nor was he answering his phone. I will be there tomorrow,” Donnie wrote as he prepared to board a flight from his home in Maui to Mazatlan.
Soon they bought a house together in the District, fixing it up in the evenings. And even after their breakup, after O'Neil moved to Mexico and Brian moved to Maryland, they remained good friends. The same charisma that had made him the centre of attention as a kid in Chevy Chase, Maryland - leading his little brother Chris and their friends through Rock Creek Park, refereeing fights after school at Blessed Sacrament, captaining dodgeball games - made him popular in the gay-friendly resort town.
The FBI agent had warned him not to look at O'Neil's face, so Donnie identified his little brother by the Irish family crest tattooed on his shoulder.
Mexican law does not allow Mexican media to fully identify suspects until they have been convicted.
They were eating seafood at a restaurant on the malecón when the Mexican's phone suddenly began to buzz.