DNA testing is the latest technique police will use to find the Lancaster rapist.
The rape, and an earlier indecent assault, have also been linked to another incident in the same area at 2.30am on March 4.
A woman returning to her home in Moor Close, where the rape took place, from the town centre noted a man in front of her, who she believed was performing a sexual act, as she walked up Quarry Road. She slowed down to try and lose the man, then sneaked past him as he talked to another man who approached him on a bike, but he followed her along St Peter's Road. As she got closer to her front door, she realised the man was still behind her and rushed to her home.
She described the man as white, in his mid to late 20s, wearing a white sweater and faded jeans. He had light hair.
DI Colin Fish, who is leading a team of 20 officers investigating the case said: "If you were the cyclist concerned, we would be ask that you come forward and talk to us."
The man is described as riding a mountain bike and wearing a baseball cap.
Police are now in the process of selecting men from the area for DNA testing. They have assured men who are asked to take part that the DNA sample, which is taken painlessly in a simple operation, will be destroyed at the end of an investigation.
When asked by The Citizen how likely it was that the rapist will give his DNA, Det Insp Fish said: "Clearly, if anybody refuses to provide a sample we will be looking to move on to another stage of the investigative process with that individual."
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