A teenage girl reported that the assault took place in an alleyway off of Post Office Walk, Harlow, between 5.30pm and 6.30pm yesterday evening, Monday 15 November.
Detective Inspector Brian Palombella, who has been leading the investigation, said:
“Following the incident, the victim spoke with two women and a man in Harlow town centre to ask for help, as she believed the suspect may have been following her.
“If you were one of these individuals, I’d ask that you please get in touch with us as you may hold crucial information.
“I know this will be alarming for the local community, but please rest assured that our teams have been working through the night into today to follow all lines of enquiry.
“If you may have witnessed the incident, have Ring doorbell footage from the area or have any information which may aid our investigation, please contact us.”
The incident number to quote is 1069 of 15 November.