DC Michele Green said: “We are investigating a report of a serious sexual assault on a female on the outskirts of Exeter in the early hours of Sunday, July 10.
She added: “A man in his 20s has been arrested in connection to this matter and has been released on police bail with strict conditions.
“As part of our enquiries, we need to identify a person or people who we believe were driven from Exeter City Centre to Silverton between 3.30am and 4am on Sunday, July 10.
“The car used was a black Skoda Octavia and the driver may have been known or unknown to the passenger or passengers and dropped them off in the general area of Wyndham Road and St Annes Place.”
DC Green continued: “This person or people may have information vital to the investigation, so if you did accept a lift from Exeter to Silverton on the night around these times, please contact us immediately.
“We would also like to hear from anyone who in the past couple of weeks has accepted a lift from a person driving a black Skoda Octavia after a night out in and around the Exeter area.
“Anyone with any information is asked to contact police on telephone 101 or email: [email protected] quoting crime reference CR/061021/22.”