A US Border Patrol agent has been arrested on suspicion of killing four women in two weeks and kidnapping a fifth.
A woman allegedly abducted by Juan David Ortiz had been able to escape and alert officers, according to local media reports.
The 35-year-old suspect, an intel supervisor for the Border Patrol, was found hiding a car park in Laredo, Texas, at around 2am after he initially fled police on Saturday.
He is alleged to have carried out the killings within the past two weeks.
Webb County Sheriff Martin Cuellar said in a statement: “We feel that our efforts have gathered strong evidence against this killer.
“Our community is safe from this killer.”
Despite Mr Cuellar’s use of language, Ortiz has only been arrested and is yet to stand trial.
The sheriff added that the suspect, who has worked for Border Patrol for a decade, would be charged later on Saturday.
Webb County district attorney Isidro Alaniz said: “We do consider this to be a serial killer.”
Mr Alaniz said investigators are still trying to determine a motive for the killings, and that they believe Ortiz acted alone.
He said all of the women worked as prostitutes.
The names of the four women have not been revealed.
The bodies of two them were discovered earlier this month along Interstate 35 in rural northwest Webb County, according to reports.
The third and fourth were found in the same area this weekend.
Andrew Meehan, a senior US Customs and Border Protection official, said in a statement that the agency was co-operating fully with investigators.
His statement added: “Our sincerest condolences go out to the victims’ family and friends.”
US authorities plan to provide another update on the investigation on Monday.