Detective Chief Inspector Al Pitcher said: “Today, our thoughts remain with the family members who are coming to terms with their loss.
“We are grateful to the people who have already spoken to us and helped with our enquiries. We would ask anyone who was at the beach at the time, and who has not yet spoken with officers, to please get in touch, to help us understand what happened.”
At this stage of our enquiries, we believe those involved in the incident knew each other, police also said.
Anyone who was in the area at the time and has information or footage which may assist the police investigation is asked to contact them on 101 and quote incident 1090.