A woman was sexually assaulted in a block of flats.

The woman was at the flats at 11.30pm last Thursday and was making her way to the top floor of a three-story block of flats.

On reaching the top of the stairs she was attacked by a man who had been crouching in wait and was thrown to the floor, punched in the face and sexually assaulted.

She managed to fight off the suspect who ran off.

He is described as five ft and eight ins tall and was wearing dark clothing.

PC Lyndsey Booth said of the attack at Boothroyd Green, Dewsbury: “This was a nasty attack on a lone female which has left her very distressed.

“We are keen to hear from anyone who was in the area at the time and may have witnessed this attack or seen the suspect running from the scene.

Please contact me on 101 or ring Crimestoppers anonymously on 0800 555111.”

In unrelated investigations, police would like to speak to the people pictured in the image gallery below. The people pictured in the images may be witnesses as well as suspects. If you recognise anyone, contact police on 101 quoting the reference number on the image caption.