A U.S. Border Patrol agent accused of killing four women was indicted Wednesday on a capital murder charge, officials announced.

Juan David Ortiz, 35, was arrested in September in Laredo, Texas, and initially charged with four counts of murder, aggravated assault and unlawful restraint in the deaths of the women, but Webb County prosecutors upped the charges after he allegedly confessed to the killings.

BORDER PATROL AGENT ARRESTED, ACCUSED OF KILLING 4 WOMEN AND KIDNAPPING A 5TH

District Attorney Isidro Alaniz said Wednesday that Ortiz, a Navy veteran, thought he was doing a public service by killing the women, who were identified as sex workers.

"The scheme in this case, from Ortiz's own words, was to clean up the streets of Laredo by targeting this community of individuals who he perceived to be disposable, that no one would miss and that he did not give value to," Alaniz said at a news conference.

"The evidence that was presented to the grand jury this morning showed that he killed these four innocent individuals in a cold, callous and calculating way," the prosecutor added.

Alaniz said that if Ortiz is found guilty of the murders, he'll seek the death penalty. He previously said investigators considered Ortiz a "serial killer."

'SERIAL KILLER' BORDER PATROL AGENT ACCUSED OF 4 MURDERS HELP ON $2.5M BOND

Ortiz was working as a Border Patrol intel supervisor when he allegedly committed the September slayings. Officials at the time said they were alerted to Ortiz when a fifth woman, identified as Erika Pena, apparently escaped after the agent pulled a gun on her, and asked a nearby state trooper for help.

Authorities said Ortiz knew most of the victims and targeted them. Melissa Ramirez, 29; Claudine Luera, 42; Guisela Alicia Cantu, 35; and Janella Ortez, a 28-year-old transgender woman, were all killed.

Ortiz, according to court documents, confessed to investigators that he had killed four people. All of the women killed had been shot, but one died of blunt force trauma, the district attorney said Wednesday.

Fox News' Paulina Dedaj and The Associated Press contributed to this report.