(CNN) -- Police say they have a confession from a Texas Border Patrol agent they suspect of being a serial killer, but many loose ends and questions remain -- chiefly, whether prosecutors will seek the death penalty.
It could take as long as 90 days to determine whether prosecutors will pursue capital murder charges against Juan David Ortiz, 35, accused of killing four women in and around the border town of Laredo, Texas, Webb County District Attorney Isidro Alaniz said during a Monday news conference.
Another loose end: Are there more victims?
Asked by a reporter if he was certain they had identified all of Ortiz's victims, Chief Deputy Federico Garza of the Webb County Sheriff's Office replied, "We're not confident (of) that, sir."
He added, "We will do historical research everywhere that he has been to see if we have a pattern of victims."
Garza provided additional details about what happened after would-be victim Erika Pena escaped Ortiz, who was holding her at gunpoint, and ran to a state trooper who was fueling up at a nearby gas station -- essentially cracking the case for police.
Ortiz, a supervisory Border Patrol agent with access to U.S. Customs and Border Protection intelligence, went home after Pena jumped out of his truck around 9:14 p.m. Friday, and Garza said he was ready for a showdown. He had numerous weapons at his home in north Laredo, the chief deputy said.
"He was loading up all those weapons thinking that the (state troopers were) going to confront him and he was looking at a confrontation," Garza said. "Thank God that didn't happen."
Ortiz also posted goodbye messages to his family after Pena escaped, telling his wife and kids he loved them and "Doc Ortiz checks out. Farewell," said Yanira de Leon, a spokeswoman for the Webb County District Attorney's Office.
Roughly three hours after Pena's escape, law enforcement officers were alerted to be on the lookout for Ortiz, and it took another hour before state troopers first encountered him. In that time, he killed two more victims, according to a police affidavit.
When the troopers found his truck at a gas station in Laredo, Ortiz had gone inside to use the restroom, Garza said. He had left a gun in his vehicle. Troopers confronted him and one tried to deploy a Taser on Ortiz, but he escaped. From there, he ran to Hotel Ava, formerly a Ramada Inn, and hid in the hotel's parking garage.
When a Webb County SWAT team and state troopers found him around 2:34 a.m. Saturday, Ortiz appeared ready to die, Garza said.
"He was trying to commit suicide by cop," he said. "He was going to try to use his phone to make it look like it was a weapon."
Police weren't fooled and took him into custody, where he gave a verbal confession to killing four women between September 3 and early Saturday, all of whom he picked up in a prostitution hub of Laredo, authorities said.
He selected the women, who he knew, based on their vulnerability and "the dislike that he had for this community of people," Garza said.
"At one point, Ortiz was able to gain their trust and viciously shot them," he said.
Garza identified three victims as Melissa Ramirez, 29, Claudine Luera, 42, and Ricky Janelle Ortiz, 28. Janelle Ortiz was a transgender woman, according to police and the funeral home handling her burial.
On Wednesday, authorities released the name of the fourth victim: Guiselda Alicia Cantu, 35, who was identified following an autopsy.
The discovery of her body on Interstate Highway 35 early Saturday was reported to the Webb County Sheriff's Office, which is investigating along with the Texas Ranger Division, authorities said.
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