A man made an "inappropriate sexualised gesture" to a teenage girl while she was running on the Downs.
This is the third incident on the Downs throughout March, where women have been targeted.
Officers have stepped up patrols in the area since a jogger was sexually assaulted on Clifton Down on March 15.
Rachel Stride, 21, was sexually assaulted near Bristol Zoo Gardens at around 7.50pm on Monday (March 15).
She feared for her life when a man dressed all in black ran up behind her and made a “really aggressive grab” for her backside.
On that occasion, police quickly attended the scene and five police cars and a dog unit were believed to have been present.
A search of the area was conducted around Ladies Mile, but the offender was not seen.
Two weeks before, Samantha Steele, 25, was left in “a state of shock” after a man groped her backside near Upper Belgrave Road.
This week, a teenager approached Sergeant Stuart King who was carrying out a vehicle patrol of the area at about 11.20am on Tuesday (March 23).
She said a man in a white van had just made an inappropriate gesture towards her.
A 43-year-old man has agreed to attend a police interview about the incident.
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Sgt King said: “Our visible presence at the scene highlights our commitment as a force to protect people from harm.
“This young woman should be able to exercise without the risk of sexual harassment. However, we’re grateful she has reported this incident to us so we can investigate and seek to identify the perpetrator.
“We would encourage anyone who has witnessed this offence, or experienced the same happening to them, to call us on 101 quoting reference 5221061813 .”
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