Three women chased a cyclist as she was riding along a road in Scunthorpe, causing her to fall from her bike.
The incident happened on Frodingham Road in Scunthorpe on Saturday, August 13.
The woman was riding along the at around 2am when three women chased her and pulled her clothing.
She suffered bruising and swelling to her right forearm which did not require hospital treatment.
All women were described as white and aged between 18 and 20-years-old.
Two of the women were between 5ft 7 ins and 5ft 8 ins tall and the third was much shorter at less than 5ft tall.
One of the taller women was wearing a black and white horizontal stripe knee length dress and was of medium build with straight brown shoulder length hair.
The second of the taller women was wearing tight fitting jeans and a white T shirt and of slim build with “dirty blonde” hair.
The third woman, who may have been slightly younger than the accompanying two was said to have long blonde hair and was wearing a tight black skirt and a white top.
Anyone with information is asked to call Humberside Police on 101 quoting crime reference number 2207823.
Calls can also be made anonymously to Crimestoppers on 0800 555 111.