Detectives investigating the rape and attempted murder in Beeston have released an image of the rock used by the attacker to bludgeon his 18-year-old victim.
They are asking residents to help identify where it came from.
Lead investigator Det Supt Nick Wallen said: “We have released an image of the fist-sized stone that he used to repeatedly strike the victim over the head during the attack.
“It was recovered from the scene and we believe the offender brought it with him to use as a weapon.
“It is quite distinctive as an object and we would ask people to let us know if they recognise it as something that has come from their garden or elsewhere, particularly if they live somewhere on his route towards the crime scene along Cemetery Road from the direction of Holbeck.
“The stone has been subject to extensive forensic examination and we are working with a specialist geologist to establish where it may have come from.”
Anyone with any information is asked to contact the Homicide and Major Enquiry Team on 01924 334710 or via 101 or call Crimestoppers anonymously on 0800 555 111.