The morning commute from their oceanside homes in Tijuana had become routine for friends Sergio Luna and Kevin Romero. The Californians, who had moved to Mexico to save money, liked to beat the congestion at the border crossing by arriving before 3 a.m.
But Monday morning they never made it to their jobs in San Diego.
As they sat in their Mazda pickup truck in the line of traffic, a gunman tapped on the window and fatally shot both men with a 9-millimeter weapon, according to Baja California authorities. The gunmen fled, authorities said, leaving behind five spent cartridges and few other clues.
Mexican authorities have not identified a motive or a suspect in the attack, which took place at 2:40 a.m. An earlier report that one of the men was carrying a small amount of drugs was not accurate, according to the Baja California attorney general's office.
Investigators were looking into the possibility that the attack stemmed from "personal" reasons, according to the attorney general's office. Luna had gotten into a fight with another man recently, according to friends who expressed concern about a retaliatory attack.
Drug war violence has diminished substantially in the Tijuana area in recent months, and U.S. and Mexican sources said the attack did not appear to be linked to organized crime groups.
The men were killed about half a mile south of the San Ysidro Port of Entry as they inched their way forward in one of the lanes approaching the border crossing, authorities said.
Luna, 25, and Romero, 28, were on their way to work at a beer equipment maintenance company in San Diego, a routine they had followed for several months, according to Matt Pelot, the owner of the company where they worked.
Pelot and other friends said they were hard workers who endured the sleep-depriving commute for family and economic reasons.
Luna, an aspiring mixed martial arts fighter originally from Bakersfield, was training for a bout in June. Romero had moved to Tijuana to live with his girlfriend because she didn't have a visa to enter the U.S.
"They would come up and greet you with a handshake and a ton of respect. They were just good guys," said Pelot, the owner of West Coast Beverage Maintenance, a company that services draft beer equipment for bars and restaurants.
Northern Baja California, with its scenic coastline lined with relatively inexpensive homes and condominiums, is home to thousands of Americans, many of them senior citizens or young people who enjoy oceanfront living for a fraction of the cost north of the border.
Luna shared his home with his fiance in the upscale Playas neighborhood, where he liked to train on the beach, friends and relatives said. Robert Breslin, his former coach, said Luna was a gym rat who was trying to climb the ranks in the mixed martial arts fight circuit.
A Mexican American who spoke Spanish, Luna moved to Mexico to improve his quality of life, Breslin said.
"Living in San Diego was draining all of his money. He enjoyed the Mexican people, the lifestyle, and he just knew he could live better and have more in Mexico," Breslin said.
Romero, originally from the San Diego area, also lived near the beach with his girlfriend and her son, who he had just adopted, Pelot said. Tall and weighing more than 250 pounds, Romero trained with Luna and also knew how to take care of himself, friends said.
The men shared long days. After crossing the border, they would take a short nap at the house of Romero's relatives, then get up and work a full day cleaning beer lines at restaurants, casinos and bars. Luna still found time to train for upcoming fights.
"He would sleep in the gym, that's how committed he was," Breslin said.