US border patrol agent charged with murder 'after two-week killing spree'

Juan David Ortiz had worked as a supervisor for Customs and Border Protection for ten years

Law enforcement officers at the scene where the fourth victim's body was found on Saturday (AP)

A US border patrol agent has been charged with murdering four women in a two-week "serial killing spree" that ended when a fifth woman escaped.

Juan David Ortiz, 35, was arrested on Saturday after being found hiding in a truck in a hotel car park in the city of Laredo in southern Texas.

He had worked as a supervisor for Customs and Border Protection for ten years and investigators are still trying to determine a motive for the killings.

"We do consider this to be a serial killer," said Webb County District Attorney Isidro Alaniz.

Authorities believe Ortiz had killed all four victims since 3 September.

Texas Rangers began investigating after the body of mother-of-two Melissa Ramirez, 29, was found in Laredo near an intersection with Highway 255, according to a report in the Laredo Morning Times.

The second victim, 42-year-old Claudine Anne Luera, was found seriously injured off the same highway on Thursday morning and died in hospital the same day.

Law enforcement officers recovered the bodies of the third and fourth victims along Interstate 35 in rural northwest Webb County this weekend.

"The manner in which they were killed is similar in all the cases from the evidence," said Mr Alaniz.

"It’s interesting that he would be observing and watching as law enforcement was looking for the killer, that he would be reporting to work every day like normal.

"In our opinion he is the sole person responsible for this horrific serial killing spree."

According to local media reports the victims all died as a result of a gunshot wound to the head.

Ortiz picked up another woman but she realised she was in danger and tried to get away, Mr Alaniz told the Texas Tribune.

"When she tried to escape from him at a gas station that's when she ran into a state trooper," he said.

Troopers confronted Ortiz at 2am on Saturday but he ran off to a nearby hotel in central Laredo and was later found hiding in a truck in the parking area.

"We feel that our efforts have gathered strong evidence against this killer," Webb County Sheriff Martin Cuellar said in a statement. "Our community is safe from this killer. My condolences to the families of the four victims who were murdered within the past two weeks."

He has been charged with four counts of murder as well as aggravated assault and unlawful restraint.

US Customs and Border Protection issued a statement saying that it was fully cooperating with the investigation.

"Our sincerest condolences go out to the victims' family and friends," said Andrew Meehan, Assistant Commissioner for Public Affairs.

"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."

Additional reporting by Reuters and Associated Press