A woman was sat in a park when she was approached by a male who touched her leg and made sexual comments.
The woman, in her thirties, was sat alone in Alfred Rose Park in Aylesbury on Friday evening when the upsetting incident happened.
At around 8.25pm, the man touched her leg and made inappropriate comments before running off in the direction of the cricket pitches.
He is described as a white male teenager, aged between 16 and 18, of slim build and around 5ft 10ins tall.
He had dark hair, a small amount of facial hair and "wonky" teeth.
He was wearing a shiny black puffa-style jacket with ripped, dark blue coloured jeans.
Police want to hear from anyone who saw what happened as they investigate the sexual assault.
You can call 101 quoting reference number 43210280683 or contact Crimestoppers anonymously.
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