The man police wish to speak to (circled) is believed to be in his 20s
CCTV images of a man suspected of carrying out a series of violent sex attacks in Bristol have been released.
The attacker, who targeted lone women, is thought to have struck seven times in a five-week period, in Park Street and Whiteladies Road in Clifton.
The images show a man following women on different days, moments before the women were attacked.
Most of the victims were talking on a mobile phone or listening to music and two were attacked on their doorstep.
A £5,000 reward has been offered for information leading to an arrest.
The attacks happened in the early hours or in the evening between 6 October and 21 November last year.
All of the women, aged between 20 and 27 and four of whom were students, were approached from behind and pushed to the ground before being sexually assaulted.
Until now, five women were thought to have been assaulted, but police revealed two more victims had recently come forward.
CCTV footage taken from shops and pubs show a man following different women on 8 and 21 November.
Both images were captured moments before the women were attacked.
Hundreds of hours of CCTV footage from the area has been searched
Det Insp Edward Heath said the attacks became increasingly violent.
"The first offences were relatively minor but the last offence was significantly more dangerous," he said.
"This is a man who has a propensity to commit the most serious sexual assaults.
The suspect is white, believed to be in his 20s and about 5ft 10in tall and was wearing dark clothing.
Police arrested two men in November, including a third-year Bristol University student, but both were released without charge.
DI Heath said he was sure that someone would recognise the man in the images.
"It may be that this man has boasted about what he has done to his friends or family and I would implore them to come forward," he said.
"Whiteladies Road seems to be the key area and it may be that the offender lives in the area.
"Women should take care when they go out, and go out in pairs, and be aware of their surroundings."