British Transport Police is appealing for information after a teenager was assaulted on a train travelling between Boston and Skegness.
Officers say a person argued with a teenager before assaulting them twice.
The incident happened on August 19 at around 3.30pm.
Officers believe the woman in the image may have information which could help with their investigation.
A BTP spokesman said: “Anyone who recognises her is asked to contact BTP by texting 61016 or by calling 0800 40 50 40, quoting reference 2400104836.
“Alternatively, you can contact Crimestoppers anonymously on 0800 555 111.”
