A robber who has launched a series of frightening and bizarre attacks on women on a stretch of towpath in Oxford is being hunted by police.

The four assaults took place over a five-day period ending last Tuesday in which the male teenager used a BB gun, a baseball bat and a fire extinguisher to threaten his victims.

The incidents took place along a half-mile stretch of the River Thames towpath between Folly Bridge and the Oxford University college boathouses on the other side of the river.

Detectives say they are hunting the man, who may have mental health problems, before he strikes again.

He is described as being a white youth aged 17 to 18, 5ft 9ins, pale-skinned. He was wearing a dark-coloured hooded top and dark tracksuit bottoms. Officers are now studying CCTV footage from cameras at Folly Bridge in a bid to catch him.

Dc Lewis Mayling, of Oxford Police robbery team, said: "The varying severity of the attacks means there could also have been other minor incidents along the towpath that haven't been reported.

"We would like to hear from anyone who has seen something suspicious over the last two weeks.

"Please contact us if you know about these incidents, or if you have seen a young man acting strangely along this stretch of the Thames.

"We advise residents, especially women on their own, to take care when using the towpath after dark because it is unlit."

The first incident took place on Friday, February 23.

Two female Oxford University students were returning from the boathouses at 8pm when a youth jumped out from behind some bushes and shot at them with a BB gun. Neither woman was hit, and the man ran off.

The following day, shortly before 9.30pm, a 21-year-old female jogger was hit in the chest with a baseball bat and had her MP3 player stolen.

The hooded teenager is also being linked to an assault on a 27-year-old woman at 8pm on Monday, February 26.

The victim was threatened and then chased and grabbed her scarf around her neck. Her assailant was believed to be carrying some kind of baseball bat, stick or club. Following that incident, Lydia Smears, a third-year English student at Mansfield College, told the Oxford Student newspaper: "I heard screaming and the girl came towards me saying 'Don't go there. He is crazy - he has got a bat'."

On Tuesday, February 27, at 5.30pm, a youth sprayed a number of people with a red fire extinguisher in the same area before running off.

The incidents on February 23 and February 27 were revealed by the police today. Detectives say the delay in releasing the information was due to third parties reporting the crimes, rather than the victims.

A man fitting the attacker's description was arrested last Wednesday but was released on bail and then released without charge.

Anyone with any information should call Dc Mayling on 08458 505505.