Police have released CCTV images of a man they want to speak to in connection with two sexual assaults.
Officers investigating the attacks in St Ives, Cornwall, said one of the women, in her 30s, sustained serious neck injuries consistent with being strangled.
She was attacked overnight between 18 and 19 September on Portminster Beach.
A 32-year-old man previously arrested in connection with that assault has been released with no further action.
The first assault also took place at Porthminster beach, early on 23 August.
Det Insp Pete Found said both women had been subjected to "serious" sexual assaults and the force believed the attacks were linked.
He said CCTV footage from the Tregenna Hill area of St Ives showed a person who may have information which is "key" to the investigation.
"As you can see in the footage, the person is male and wearing a black hooded top with a very distinct pattern on the back," said Det Insp Found.
"We are appealing for anyone with information to come forward and contact us."
Det Insp Found said such incidents were rare in St Ives but urged people to remain vigilant.
He said: "We ask that people look out for each other and to not walk alone in isolated areas, stay with friends during a night out and ensure journeys home are arranged."