A murder investigation has begun after a man was found with stabbed to death near a bus station.
Police said the man, who they believe to be 41-year-old Christopher Ritchie, was on crutches at the time.
He was discovered at about 08:30 GMT in Mitchell Street behind Durham station and treated by paramedics but died at the scene.
Det Ch Supt Adrian Green, who is leading the investigation, said they were searching for the suspect.
Mr Ritchie was a distinctive-looking man and "well known in that area of the town centre", Det Ch Supt Green said.
"He was on metal crutches at the time, wearing a dark puffa jacket, dark trousers, black Nike trainers and a dark blue, black and turquoise Hollister baseball cap," he said.
Students may have information about what happened, he said, appealing for anyone who saw Mr Ritchie or what happened to come forward.
A cordon was put in place around the station, with bus services diverted, while police made inquiries.
A force spokesman said: "This investigation is in the very early stages and we are working to establish exactly what has happened."