The woman in the white pickup was feeling increasingly uneasy about the driver, whom she knew only as "David." Two fellow sex workers in Laredo, Texas, had been recently killed, and one of them was her friend Melissa.
The man and the woman had already been at his house, where she had discussed Melissa. He had reacted strangely, she later told authorities, and the situation had grown so tense that she vomited in the front yard before they left for a gas station. The woman's mind lingered on Melissa. She wanted to keep talking about her.
He produced a gun in response and grabbed hold of her shirt. She managed to jump out of the truck and into the night, her shirt torn from her body. He fled, and she found a state trooper fueling up nearby. She told the trooper where the man lived.
That information led officers to Juan David Ortiz, a supervisory Border Patrol agent. He had been hiding in a hotel parking lot after fleeing from officers and was arrested at 2:30 a.m. Saturday, according to an affidavit provided to The Washington Post by county prosecutors.
Ortiz, 35, confessed to the two September murders, according to the document.
But he had other confessions to make.
He had killed two more people in the five hours between the assault on the escaped woman and his capture.
"We consider this man to be a serial killer who was preying on one victim after another," Webb County Sheriff Martin Cuellar said.
Isidro Alaniz, district attorney for the Webb and Zapata counties, said he believed Ortiz acted alone in the murders while off duty. He is a 10-year veteran of the agency and worked in intelligence, authorities said.
Ortiz was charged with four counts of murder, aggravated assault and unlawful restraint, Alaniz told The Washington Post on Sunday. All of his victims were sex workers, including the woman who escaped, the district attorney said, and there are signs that at least some of them were not chosen at random.
"Evidence points to him having knowledge and contacts within the [sex worker] community," Alaniz said, including Melissa Ramirez, the first woman Ortiz said he killed. But Ortiz does not appear to have known the last two victims, he said.
Alaniz is also overseeing another case involving a Border Patrol agent in Laredo, a man accused of killing his lover and their 1-year-old son.
The victims in the Ortiz case were killed or left for dead in rural parts of Webb County, which borders the Rio Grande. Laredo is about 150 miles southwest of San Antonio. The first two were U.S. citizens, but Alaniz said authorities have not released details on the last two. The Post is withholding the name of the woman who escaped.
The Texas Rangers and the Webb County Sheriff's Office are investigating the murders, authorities said. In a statement, Customs and Border Protection said it was cooperating with investigators.
"While it is CBP policy to not comment on the details of an ongoing investigation, criminal action by our employees is not, and will not be, tolerated," said Andrew Meehan, a spokesman for the agency. "Our sincerest condolences go out to the victims' family and friends."
The arrest record recounts the brutal symmetry of the killings, along with the alarm that spread within the seemingly tightknit community of sex workers after the first two slayings.
Ortiz told investigators that he picked up Ramirez on Sept. 3. They drove about 30 miles from town, and she got out of his vehicle to urinate off a country road cutting through dense shrub land.
Then he shot her in the head multiple times, the affidavit says. She was later found dead. Ramirez was a mother of two, the Laredo Morning Times reported.
Ten days later, investigators said, Ortiz drove Claudine Ann Luera outside the city a few miles from where he said he killed Ramirez.
He told investigators that she accused him of being the last person to see Ramirez alive.
Ortiz said that she got out and that he shot her in the head, the document says. Luera was found alive and died of her wounds at a hospital.
The next two killings occurred in the hours after the woman escaped early Saturday, authorities said. Ortiz told investigators that he picked up an unknown woman whom the document identifies only as "Jane Doe."
He told her to exit the vehicle along Highway 35 outside Laredo, then shot her multiple times in the head, according to the document. He then went back to the city. While in Laredo, he picked up another person — whom Alaniz described as a transgender woman — and took her five miles from the site of the earlier killing.
Ortiz said he shot her once in the back of the head and told investigators where they could find the body. They discovered it behind gravel pits, near a single shell casing, the document says.
Alaniz lauded the woman who escaped and said perhaps Ortiz would have killed more people had she not demonstrated such bravery.
He declined to discuss any potential motives, citing the investigation.
He said Ortiz was defiant and uncooperative under questioning, at least at the start.
Detectives asked him to do "the right thing," Alaniz said. Ortiz asked for the handcuffs to come off, and the circumstances behind the killings began to trickle out, the district attorney said. One woman shot in the face. Another shot from his vehicle. There were no tears.
“This guy is cold,” Alaniz said.