Corrupt officials have given sensitive information to cartels, and waved tons of drugs and thousands of undocumented immigrants through the border in exchange for millions of dollars in bribes. Many operate at official ports of entry, undermining the billions of dollars the government has already spent on fencing, drones, radar, surveillance blimps, agents, and now, perhaps, President Trump’s border wall.

Last year, a Department of Homeland Security report found that corrupt border agents are such an urgent problem, they “pose a national security threat,” and called for more aggressive measures to root them out.

But CBP may instead relax its standards to meet hiring goals set by Trump in a January executive order that mandates 5,500 new border agents. If the agency does, it risks repeating the mistakes of a previous hiring surge in the mid-2000s, when drug cartels took advantage of lower hiring standards to infiltrate the ranks.

More common than infiltrators sent by cartels, however, are agents who go rogue to pay off debt, to help a family member, for sexual favors, or simply for a payday. For Joel Luna, a military veteran who led what looked like a law-abiding life, the trouble seemed to start with his family entanglements, according to Gustavo Garza, the prosecutor who worked on his case. “Whether he did it out of greed or out of love for his family, only he knows,” Garza said.

Police Officer Manny Ochoa responded to Robert Hannan’s panicked call. When he arrived on the scene, the victim’s “neck, where his head was cut off, was at the surface of the water,” he later recalled.

Ochoa reached under the victim’s arms and hoisted the body onto his boat, only a few hundred feet from the shore of South Padre Island, Texas, a popular spring-break destination for thousands of college students. Beach parties raged on nearby.

Some investigators believed that a propeller had cut its head off, but Carlos Garza, the lead investigator for the Cameron County Sheriff’s Department, saw a “clean cut” that made him think it was a homicide. There was also a second cut from the collarbone to the sternum that Garza determined was an unsuccessful attempt “to deflate the body” and keep it from floating.

The body was discovered just miles from the Gulf Cartel’s headquarters in Matamoros, Mexico, but local police were unaccustomed to such brutality. Texas border towns are among the safest communities in the country.

Though the head was missing, “the hands were there, the fingerprints were there,” Garza said. “We made an identification on the body.”

It was Francisco “Frankie” Palacios Paz, a Honduran immigrant who worked at a tire shop an hour from the beach. At the tire shop, investigators found co-workers who said Frankie “‘went to spring break,’ and that didn’t make a lot of sense to us,” Garza said.