RIO BRAVO — The wooden urn holding Melissa Ramirez’s ashes waits in her mother’s kitchen, part of a small altar that includes a photo of the smiling girl, another of a brother who died years earlier, and a Bible opened to Psalm 91.

Her mother, Maria Cristina Benavides still lives in fear, despite the arrest early Saturday of Border Patrol agent Juan David Ortiz, who is in jail and charged with four counts of murder in the deaths of Ramirez and three others. Investigators say he confessed to the killings.

“I don’t feel secure. I’m afraid for my grandchildren. I don’t really know who killed Melissa and I don’t know if there was more than one,” Benavides, 51, said Sunday afternoon.

Teary-eyed and sunburned from collecting donations on a street corner Saturday to pay for her daughter’s interment, Benavides spoke freely but declined to have her photo taken.

“I hurt a lot. All I want is justice. I want that guy to die in jail for taking the life of my daughter,” she said, seated in the living room of an aging mobile home under a metal shade.

“I last saw her on Aug. 31. She was here with us. They came on Sept. 5th to tell me she was killed,” she said.

Outside, Melissa’s two children, a girl, 7, and a boy, 3, played in the yard, which has a trampoline, a pink clubhouse, various mechanized vehicles and a yipping Chihuahua.

In this bustling border city of around 260,000 residents, where Border Patrol agents are part of the fabric of daily life, the news that one may have become a serial killer was especially jarring.

According to authorities, Ortiz, 35, an intelligence supervisor and 10-year veteran of the agency, confessed to killing four people over a two-week period and getting rid of the bodies in a rural area near U.S. 83 in the northwest part of the county. Ortiz was jailed on $2.5 million bond, according to the Associated Press.

Webb County District Attorney Isidro Alaniz said Saturday that investigators “consider this to be a serial killer” whose victims were believed to be prostitutes.

Alaniz described how the Customs and Border Patrol intel supervisor continued going to work as usual throughout that time. “As law enforcement was looking for the killer … he would be reporting to work every day like normal,” he said.

Two of the victims have not yet been identified.

According to the arrest affidavits, all four victims, and a fifth person who escaped and alerted police, were picked up on San Bernardo Avenue in an area north of downtown known for prostitution.

Erika Peña, who authorities said was picked up by Ortiz late Friday, told police she fled from his vehicle after he pulled a pistol on her. Earlier, she said, they had visited his house off Loop 20.

Ortiz was arrested hours later, but not before he picked up and killed two more people, according to the affidavits.

In Rio Bravo, a low-income community south of Laredo where Benavides raised her family, the dramatic news of the serial killings was just filtering out Sunday morning.

“I knew Melissa. Everyone knew her,” said R. B. Flores, 62, sitting in his wheelchair outside the Rio Bravo Meat Market, where part of the breakfast menu was posted on the bright yellow wall behind him.

“Tacos Mananeros. 99 Cents” was the heading.

“Yesterday we were selling plates of food at the church for the muchacha, for her funeral. And afterward, someone said another girl was killed. We all were shocked,” he added.

Benavides said her daughter dropped out high school when she was a junior, never really worked and developed a drug problem. Her mother took custody of her two children.

Ramirez, 29, would come and go from Rio Bravo, sometimes being away for days at a time, her mother said.

“She loved music and watching TV with the kids. They would watch cartoons,” said Benavides.

“She would cook for them when she was here, sometimes all three meals. She didn’t like me scolding them. ‘They’re little,’ she would tell me,” she added.

Ramirez never mentioned Ortiz to her mother.

“She always told me about her boyfriends, but she never said she knew a Border Patrol,” she said.

Claudine Anne Luera, 42, the other victim who has been identified, grew up in Laredo and was the third of four sisters, and mother of five children.

Her younger sister, Colette Mireles, said Luera had gone from being a stay-at-home single mom caring for her children to living on the streets.

“She chose the street life. It’s just sad that her habits got the best of her, that life got the best of her,” Mireles said.

While the family had always feared that Luera might die of an overdose, the news that she was brutally slain was shocking.

According to the affidavit, she was killed by Ortiz on Sept. 13, after she accused him of being the last person seen with Melissa Ramirez.

She was shot multiple times in the head and left to die.

“She didn’t deserve that,” said her sister.

Staff Writer Diana R. Fuentes contributed to this report.