Police are appealing for witnesses after a teenager reported she was raped in Stowmarket at the weekend.
A 19-year-old woman reported to officers that she was raped at around 2am on Sunday in the vicinity of the Recreation Ground.
She is being supported by specialist trained officers, as detectives have been making initial enquiries into the incident.
A 26-year-old man was arrested on suspicion of rape on Sunday evening and taken to Martlesham Police Investigation Centre for questioning. He has now been released under investigation pending further enquiries.
Detectives are appealing for anyone who was near the Recreation Ground between 1.30am and 2.30am on Sunday morning to contact them.
Officers are urging members of the public to remain vigilant when out at night, to plan your journey home and avoid going off alone.
Call the West Safeguarding Unit at Bury St Edmunds Police Station on 101 quoting 17554/18 or contact the charity Crimestoppers anonymously on 0800 555111.