Police investigating two rapes in Greater Manchester, two years apart, are hoping an appeal on BBC's Crimewatch can help trace the attacker.
Detectives have linked the rapes of two 21-year-old women, who were both attacked as they walked in Fallowfield in the early hours.
The first happened on 11 May 2007 and the second on 21 May 2009.
The second victim will give an anonymous interview during Tuesday's Crimewatch programme.
The broadcast will feature reconstructions of both rapes, the first of which happened at about 0200 BST, when the victim was walking along Whitby Road.
Police said the attacker pushed her into an alley and throttled her until she was unconscious, before raping her.
In the second attack, the woman was walking home from work along Egerton Road at about 0310 BST when she was grabbed from behind and dragged down an alley near the junction with Mauldeth Road.
Police said that after the rape the attacker told the woman to stay in the alley until he had left.
In both cases the attacker is described as Asian, 6ft (1.82m) tall, aged in his early 20s, of slim build and was wearing dark clothing.
In the hours before the second attack, at about 0025 BST, another woman was seen walking down Egerton Road towards Mauldeth Road and is believed to have been followed by the offender.
Det Insp Colin Larkin said: "Despite our continued efforts the man we believe could be responsible for both of these attacks is still at large.
"We hope the appeal on Crimewatch will convince any members of the public who can help our inquiries to pick up the phone and call us.
"We want to reassure the communities of south Manchester that highly trained officers have been fully investigating both attacks, but we also need help from the public."
Crimewatch will be shown on BBC One at 2100 BST.