SAN ANTONIO (AP) — A former Border Patrol agent who confessed to killing four sex workers in 2018 was convicted Wednesday of capital murder, after jurors heard recordings of him telling investigators he was trying to "clean up the streets" of his South Texas hometown.

Juan David Ortiz, 39, receives an automatic sentence of life in prison without the possibility of parole because prosecutors decided not to seek the death penalty.

Ortiz, a Border Patrol intel supervisor at the time of his arrest, was accused of killing Melissa Ramirez, 29, Claudine Anne Luera, 42, Guiselda Alicia Cantu, 35, and Janelle Ortiz, 28. Their bodies were found along roads on the outskirts of Laredo in September 2018.

During the trial that began last week, jurors heard Ortiz's confession during a lengthy taped interview with investigators.

Ortiz told investigators he had been a customer of most of the women, but he also expressed disdain for sex workers, referring to them as "trash" and "so dirty" and insisting he wanted to "clean up the streets."

He said "the monster would come out" as he drove along a stretch of street in Laredo frequented by the women.

Defense attorneys said Ortiz was improperly induced to make the confession and that it should not be considered. Defense attorney Joel Perez argued that Ortiz, a Navy veteran who had been deployed to Iraq, was suffering from post-traumatic stress disorder, had been suffering from insomnia, nightmares and headaches, and was medicated and had been drinking that night.

Prosecutors told jurors it was a legal confession provided by an educated senior law enforcement official who was not having a mental breakdown.

Erika Pena testified that Ortiz picked her up on the evening of Sept. 14, 2018, and that she got a bad feeling when he told her he was the "next to last person" to have sex with Ramirez, whose body had been found a week earlier. She testified that he told her he was worried investigators would find his DNA on the body.

"It made me think that he was the one who might have been murdering," Pena, 31, told the jury.

Pena escaped from his truck at a gas station after he pointed a gun at her, and she ran straight to a state trooper who was refueling his vehicle. Ortiz fled.

Authorities tracked Ortiz to a hotel parking garage in the early hours of Sept. 15, 2018, and he was arrested.

Capt. Federico Calderon of the Webb County Sheriff's Department testified that officers who arrested Ortiz knew about the slayings of Ramirez and Luera, and while chasing him after Pena's escape learned that a third body — later identified as Cantu's — had been found. But Calderon said it wasn't until Ortiz's confession that they learned Janelle Ortiz had been slain.

Webb County Medical Examiner Corinne Stern testified that Ramirez, Luera and Janelle Ortiz were fatally shot while Cantu, who was shot in the neck, died of blunt force trauma to the head.

The bullets collected from the crime scenes came from the same gun, and matched the weapon found in Juan David Ortiz's pickup, a ballistics expert testified.

Ortiz served in the U.S. Navy for nearly eight years, until 2009, holding a variety of medical posts and served a three-year detachment with the Marines.