British Transport Police officers who arrested a man on suspicion of sexually assaulting a toddler are appealing for further information.
The man; aged 44 and from Luton, is alleged to have approached a mum and her two young children.
He then inappropriately touched the youngest child, a girl.
The male was arrested at Norwich station and interviewed by the police.
The BTP has confirmed that he has since been released under investigation while officers gather further information.
The incident happened on a train approaching Norwich between 7 pm and 7.30pm on Friday 24 May.
Detective Inspector Darren Bates of the British Transport Police said:
“Clearly, this is a very serious allegation; we are committed to investigating all lines of enquiry and would like to speak to anyone who witnessed the incident.
“We would especially like to speak to two women who witnessed the offence and assisted the mum.
“They left the train at Norwich; their accounts could contain vital information.”
Any witnesses can contact BTP by texting 61016 or by calling 0800 40 50 40 and quoting reference 563 of 24/05/19.
Alternatively, call Crimestoppers anonymously on 0800 555 111.