Then, that second man -- a wealthy, 52-year-old Texas retiree named Jake Clyde Merendino -- was found stabbed to death in a ravine alongside a Mexican highway.
And authorities say his lover, and that lover's girlfriend, are responsible.
David Enrique Meza, 25, was arrested and charged in federal court Wednesday with one count of interstate or foreign domestic violence resulting in murder. His long-term girlfriend, 20-year-old Taylor Marie Langston, faces one count of obstruction of justice and one count of lying to a federal officer. Police said she claimed to be at a friend's house in Tijuana, Mexico, around the time of Merendino's death.
Meza and Langston also face one count each of conspiracy to obstruct justice, according to a news release on the website of the FBI's San Diego office
The two pleaded not guilty to the charges Thursday in a court appearance, according to the Los Angeles Times
A call placed Friday by CNN to the suspects' lawyers was not immediately returned.
Federal authorities laid out their version of what happened, claiming Meza met Merendino in 2013. At the time, Langston was allegedly pregnant with Meza's child and still in a romantic relationship with him.
Meza and Merendino rented a car last April 29 and drove into Mexico, where they finished off the purchase of a $300,000 condo in an upscale development between Rosarito and Ensenada, according to the FBI news release, citing an affidavit. They returned to the United States that afternoon and checked into the Hercor Hotel in Chula Vista, California.
The pair were back in Mexico on May 1, with Merendino at the wheel of a Range Rover and Meza riding a motorcycle. They checked into a hotel there and a motorcycle was seen leaving around 10:30 p.m., according to the FBI.
The federal agency said Merendino was last seen around 1 a.m. May 2, telling hotel security that he was leaving to help a friend stranded along a road.
The man's body was found around 3:30 a.m., with Meza crossing into the United States about a half hour later, the FBI said. Langston was about 25 minutes behind him in a black SUV with no license plates, according to the agency.
Accompanied by Langston, Meza was back at the same Mexican hotel -- having arrived there in a black SUV without license plates -- and "told hotel staff he was there to pick up his personal items from the room he'd shared with Merendino," the news release said.
Through his lawyers, Meza contested Merendino's will a few weeks later "and filed (a) handwritten will on letterhead from the Hercor Hotel (that) named Meza sole beneficiary of Merendino's estate," the FBI news release said.