A woman was sexually assaulted on a bus travelling from Milton Keynes to Aylesbury Vale on Tuesday last week.
At 4:15pm a woman in her twenties got on a 150 bus and as it was passing via Leighton Buzzard, a man got on the bus and sat next to the victim.
He sexually assaulted her by touching.
The unknown man is described as being in his forties and wearing beige trousers.
He was removed from the bus by the driver and other passengers in Bierton.
PC Natalie Powell said: “I am keen to speak to anyone that was on this bus last Tuesday, and witnessed the assault to please contact me via the 101 number.
“We are making enquiries and patrolling the area to offer reassurance to local residents and if anyone has any concerns they should speak with officers who can help to address these.”
Anyone with information regarding this sexual assault should contact Thames Valley Police via the 24-hour Enquiry Centre on 101.
If you don’t want to speak directly to the police, you can contact Crimestoppers anonymously on 0800 555 111 or online at crimestoppers-uk.org
No personal details are taken, information is not traced or recorded and you will not go to court.