Wigan schoolgirls have been targeted by an online pervert masquerading as a teen.
One local school put out a warning to parents to be on their guard after several of its students fell victim to the man.
And as counselling is offered to victims, the police are also asking for any other girls in the borough who may have been propositioned by this character on Snap Chat - who has been going under the pseudonym of Elliot Gue or Goo.
The teenagers were lulled into thinking they were speaking to a 14-year-old boy who, police say, sent them messages of a sexual nature.
But it later emerged that the person at the other end of the line was much older than he claimed.
A man - believed to be a 26-year-old in London - has since been arrested in connection with the incidents.
Det Insp Matthew Moore, based at Wigan, said: “While it is natural that parents and pupils will be concerned about the sexual nature of these messages, I want to reassure them that a man has now been arrested by the Met police in London in connection with these offences.
“Safeguarding and CSE Risk Prevention work is now being carried out by specially trained officers to help support any children who have been affected.
“Officers are also working to identify any additional children so they can contact their parents and offer advice and support.”
A spokesman for Wigan Council said it is aware of the issue but police were taking the lead on the matter.
The headteacher of the school which had put out a warning letter asked that it not be identified.
The letter to parents read: “It has come to our attention that a male from London has been posing as a 14-year-old boy and attempting to contact teenage girls in the Wigan area.
“The police are aware of the situation and have asked that we monitor the situation in school.
“His Snap Chat name is Elliot Goo. Can you please scrutinise your child’s account closely and inform us if you see this name in their contacts.
“Although we are all responsible for educating and monitoring the children’s social media activity, it is important that they only communicate with people they know in reality.
“Sometimes social media can be perceived by them as a personality contest. Can I ask that you check their friends and followers for anyone they may not know?”
The headteacher said that girls from a number of schools across the borough had been contacted.
Anyone who has yet to report such contact is asked to ring police on 101 or Crimestoppers on 0800 555111.