Juan David Ortiz has been charged with four counts of murder

A US Border Patrol agent has been charged with multiple counts of murder after four prostitutes were killed in what police have called a serial killing spree.

Juan David Ortiz was arrested after a woman, alleged to be a potential fifth victim, escaped a petrol station and alerted police.

The 35-year-old suspect was found hiding in a car park in Laredo, Texas, at around 2am on Saturday.

He has been a Border Patrol intelligence supervisor for ten years.

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

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

He said investigators are still trying to determine a motive for the killings – but they believe Mr Ortiz acted alone.

Police said two of the victims were US citizens – while the nationalities of the other two remain unknown.

They were all working as prostitutes and one was transgender.

Mr Ortiz is accused of carrying out the killings from September 3rd .

Two of the bodies were found along Interstate 35 in rural northwest Webb County earlier this month, with the third and fourth discovered in the same area this weekend. 

The investigation is ongoing.