The incident took place around 9pm on July 8th as the man was cycling down Vintergatan in central Örebro, the Aftonbladet newspaper reports.
Suddenly, someone grabbed hold of the rack on the back of the man’s bike, causing him to fall to the ground.
“The girls ran up to him and pulled the bicycle down so he fell,” Örebro police spokesperson Annika Haaster told the newspaper.
As the man was lying defenceless on the ground, the women proceeded to pull off his trousers and underwear and molest him sexually before fleeing the scene.
According to police, the 50-year-old was not otherwise beaten or physically assaulted by the gang of five girls.
The victim told police that the girl who actually pulled down the bicycle was about 175 centimetres (5 feet, 7 inches) tall and had tattoos on her forearms.
Authorities are hoping that tips from the public can help them apprehend the suspects responsible for the bizarre attack.
“It’s downright unusual for five girls [to do something like this]. Perhaps there are others who’ve had the same thing happen to them,” Haaster told Aftonbladet.