A woman was sexually assaulted after she and the man she was with were held captive for six and a half hours.
The couple were sitting in a green Rover car in Alexandra Road in Luton when two men got in and attacked them.
The man, from Milton Keynes, was stabbed before they were driven in their car 30 miles into Cambs.
The woman, 23, from London, was then subjected to a serious sexual assault in the incident, which happened between 0100 BST and 0730 BST on Sunday.
Both were then abandoned in the Hill Farm area of Papworth Everard.
Car found
The victims were found shortly after by a member of the public and have been treated at hospital for their injuries.
The Rover was found later, by another member of the public, in Roxton Road, in Chawston, north east Bedfordshire. It is being examined for forensic evidence.
One of the attackers was described as white man of eastern European appearance of thin build, 5ft 8in tall, aged in his mid 20s. He had short dark hair and wore a brown jacket and blue jeans.
The other was a white man with olive skin, of thin build, 5ft 9in tall, also aged in his mid 20s. He too had short dark hair and wore blue jeans, a blue shirt and brown shoes.
Motive sought
Det Insp Alan Postawa, from Bedfordshire Police, who is leading the investigation, is anxious to speak to anyone who may have information.
He said: "I am particularly keen to speak to anyone who saw the green Rover car in Alexandra Road in the early hours of Sunday morning.
"It may have been parked there for a while and someone may have seen it, or the offenders approach it."
"Other people may recognise the description of the offenders or have an idea of the motive behind this serious incident."