A US border agent has confessed to the murders of four women and the assault of a fifth, police records say.
Juan David Ortiz, a Border Patrol supervisor, was arrested in Laredo, Texas after the assault victim escaped and alerted the authorities.
Police said the murdered women worked as prostitutes, and that Mr Ortiz shot all four in the head.
He made a “voluntary verbal confession” to the murders and assault over a two-week period, police say.
The 35-year-old is being held on a $2.5m (£1.9m) bond for four murders, aggravated assault and unlawful restraint, according to his arrest documents.
Webb County district attorney Isidro Alaniz described the murders as a “horrific serial killing spree”, according to local media reports.
Officers arrested Mr Ortiz in a hotel car park after he initially tried to flee from state troopers.
Authorities began to look for him after a woman named Erika Pena approached an officer for help late on Friday night.
Records say Mr Ortiz picked her up that night. She managed to flee his car after he pointed a gun at her and tried to stop her from escaping.
After Ms Pena managed to get away, Mr Ortiz reportedly told investigators he picked up his last two victims.
They have not been named, but Mr Alaniz said one of them was a transgender woman.
The first two – 29-year-old Melissa Ramirez and 42-year-old Claudine Anne Luera – were shot and left on rural roads.
Ms Luera was found alive but died in hospital of her wounds.
The 35-year-old worked for US Border Patrol for almost 10 years, and went into work as normal throughout the two-week period.
He reportedly served in the US Navy prior to joining the border agency.
Ortiz is the second Border Patrol agent to be held for murder this year, after Ronald Anthony Burgos Aviles was held on two counts of murder in April.