A US Border Patrol agent has been arrested in the state of Texas on suspicion of killing four prostitutes, reports say.
Officers were looking for Juan David Ortiz after a fifth woman escaped from him and contacted police, AP reported.
Mr Ortiz fled but was arrested in a hotel parking lot in the city of Laredo.
Webb County Sheriff Martin Cuellar said police believed Mr Ortiz had acted alone.
“The county, the city can rest assured we have the serial killer in custody,” Sheriff Cuellar said. He was quoted by the Laredo Times newspaper.
He said investigators had “very strong evidence” that Mr Ortiz was behind the killings.
District Attorney Isidro Alaniz said Mr Ortiz, who had been with the Border Patrol for 10 years, was set to face four charges of murder and one of aggravated kidnapping.
Two of the victims were found earlier on Saturday and on Friday evening.
On Thursday a 42-year-old woman was found critically injured by the side of a highway and died in hospital.
The body of a 29-year-old mother-of-two was found on 4 September, the Laredo Times said.
Mr Alaniz said the cause of death was similar in each case. He said all the women worked as prostitutes and investigators were trying to find a motive for the killings.