A U.S. Border Patrol agent arrested in connection with the slayings of four people and the kidnapping of a woman who escaped was described as a serial killer who hunted for his victims, CNN reports. Juan David Ortiz, 35, confessed to killing four people between September 3 and September 15, said a criminal complaint filed in Webb County, Tx. Ortiz was charged with four murder charges and one unlawful restraint with aggravated assault with a deadly weapon, said Webb County District Attorney Isidro “Chilo” Alaniz. The bodies of four victims were found over the past two weeks. Investigators are not ruling out the possibility of more victims. The victims, who were shot in the head, were three women and a transgender woman, all prostitutes.

“He was profiling certain kinds of victims,” Alaniz said. Andrew Meehan, a U.S. Customs and Border Protection spokesperson, said, Criminal action by our employees is not, and will not be tolerated.” Alaniz said the case broke Friday when a woman was reportedly kidnapped and escaped. The victim was able to provide a detailed description of Ortiz, including his tattoos. Authorities found Ortiz at a gas station in Laredo, about 160 miles southwest of San Antonio. He fled the scene on foot and ran to a hotel, where he was found hiding in the bed of a pickup truck.