Women in Cambridge have been warned to be on their guard after police linked a string of sex attacks.
Cambridgeshire Police said they thought the same man was responsible for "sexually touching" women as they walked in the city.
Some of the six victims were students, a police spokesman said.
He said experts were trying to create a photofit image of the attacker, who was described as white, aged 20 to 30 and between 5ft 10in (1.7m) and 6ft (1.8m).
He was thought to have short dark hair and stubble and was wearing a black jacket over a grey hooded jumper.
'Struggling or screaming'
The spokesman said that in every incident over the past three months, women had been "grabbed" as they walked.
"Police are linking six incidents which have occurred in the city since 11 November," said the spokesman.
"In every incident the offender has run off when the victim began struggling or screaming."
He added: "We have spoken to universities and are warning women to be cautious. We are also increasing patrols."
Det Insp Billy Bremner said: "These six unpleasant incidents have striking similarities and we are linking them at this time."
Police said the attacks took place:
- At 0115 GMT on 11 November, when a 21-year-old woman was grabbed in Adams Road
- A 29-year-old woman was assaulted in Silver Street at about midnight on 17 November
- The following day, at around the same time, a 21-year-old woman was assaulted in Sidgwick Avenue
- A 19-year-old woman was grabbed in the same street at 0200 GMT on 2 December
- A 32-year-old woman was assaulted in Granchester Meadows at 0300 GMT on Christmas Day
- The latest incident happened in the early hours of 7 February when a 27-year-old woman was grabbed in Shelly Row at 0030 GMT. The offender ran off when she screamed.