A team of officers is combing security camera images in a bid to catch the man who indecently assaulted three women in 10 days in the West End of Glasgow.
It came as Glasgow University staff confirmed a drive had been launched to help students stay safe when they are walking alone.
Attack alarms are being handed out to women and they are being given advice on personal safety.
On January 24 at around 4.20pm, a 23-year-old woman was followed by a man before being attacked in a common close in Great Western Road.
A week later on January 31 shortly before 6.30pm, a 19-year-old woman was walking into flats in Arlington Street when she was indecently assaulted by a man.
And a 20-year-old woman was the victim of an indecent assault on Feburary 3, which happened in Kersland Street at around 5pm.
Police say the incidents are linked.
The suspect is described as white, aged between 20 and 30, around 6ft to 6ft 2in tall, slim and with black hair.
Detective Inspector Fil Capaldi, of Strathclyde Police's West End office, said: "We have a dedicated team of officers scouring CCTV and we've had a breakthrough with that. We are currently in the process of verifying images.
"There are lots of shops and businesses nearby, which all have CCTV, so we have a lot to get through and are still looking through the extensive footage.
"Our inquiries are continuing and we have teams at the laboratory working on forensic analysis."
Mr Capaldi said there had been a positive response from the public. He added: "If you see someone acting suspiciously or someone of the description we've issued don't hesitate to let us know."
Police are working with university staff and students to raise awareness of safety.
Neil Campbell, head of campus services at Glasgow University, said: "There has already been a series of meetings between police, campus security and the Student Representative Council (SRC).
"We are being kept up to date with all the developments.
"If students want to acquire attack alarms they can speak to us about that."
Sandra White, MSP for Glasgow Kelvin, said several worried constituents had been in touch with her.
She said: "I think we need to look at practical measures such as better street lighting.
"Women should be able to walk alone whenever they want."
Anyone with information is asked to call police on 0141 535 3500.