British Transport Police in Berkshire have come under fire for an appeal in which they failed to identify the gender of a person they want to speak to in connection with an indecent exposure.
Officers launched a CCTV appeal after the alleged incident at Theale train station on 2 September.
Police say two girls ages 15 and 16 were sat onboard a train when 'a person' approached the window and exposed themselves, before walking into a station shelter and performing a sex act.
But police have been criticised for not revealing whether the person they are looking for is male or female.
The Labour MP for Canterbury Rosie Duffield responded to the Twitter appeal, condemning the force for not being clearer.
Replying to the tweet, Ms Duffield said: "When women report assaults/serious incidents on public transport, do you allow them to describe the perpetrator by their sex (majority of VAWG carried out by men), or do you quiz the victim at length first in order to prioritise an alleged attacker's identity feelings?"
Posting on social media Berkshire BTP said: "Officers believe the person in the CCTV images may have information which could help their investigation.
"If you recognise them, or have any information, please contact BTP by texting 61016 or calling 0800 40 50 40 quoting reference 2200089694.
"Alternatively, you can call Crimestoppers anonymously on 0800 555 111."
Many others took to Twitter calling on the police to identify the gender of the person they are hoping to trace.
One person tweeted "Just say male. It's ridiculous to not. It's dangerous to not let the public know this is a male."
While another user defended the appeal saying: "There is a photo of the ‘offender’ which is the only description that matters. You recognise them, or you don’t."
Berkshire British Transport Police have been contacted for a response.