Officers said the suspect was about 6ft 5in (195cm) tall, of proportionate build with brown and grey hair, and blue eyes.
Police said officers were continuing to carry out inquiries to locate him and appealed to the public to provide any sightings or information regarding his whereabouts.
David Badham, general manager at Central Convenience on Walker Terrace near where the woman was found on West Hoe Road, said staff heard “screams” and people asking for an ambulance.
His shop was within the police cordon with officers asking him to keep the doors locked.
He was also told not to allow people in and out of the shop.
A resident, who asked to remain anonymous, added they were “deeply shocked and saddened” by what had happened.
