Detectives are carrying out enquiries following a third party report of concern for a woman on Weelsby Road, Grimsby at around 5am on Sunday, 9 June.
Detective Inspector Kerry Bull said: “We received a third party report in the early hours of Sunday morning, about a woman, who was unknown to the caller, as she had concerns for her wellbeing after discovering her in the street.
“The woman appeared to be injured and is believed to have disclosed that she had been sexually assaulted, before she got into a grey Nissan Qashqai and was driven away.
“We are trying to identify and find the injured woman to ensure she is OK and to offer her any support that she may need.
“I appeal directly to her, the driver of the Nissan Qashqai, or anyone who knows who she is, to please get in touch by calling our non-emergency number 101, quoting log 131 of 9 June 2019.”