A man arrested following the deaths of a 17-year-old boy and a 12-year-old girl off Bournemouth beach has been released under investigation.
A 17-year-old boy from Southampton and a 12-year-old girl from Buckinghamshire died after getting into difficulty in the water at the Dorset resort on Wednesday afternoon.
A further eight people were treated by paramedics following the incident.
A man in his 40s, who was “on the water” at the time, was arrested on suspicion of manslaughter. Dorset Police said on Thursday evening he had been released under investigation.
It comes after reports suggested a sightseeing boat, the Dorset Belle, had been impounded at Poole Harbour by police.
A police source told The Times: “This vessel is under a police cordon. No-one is permitted on board or to touch the vessel.”
Police said earlier on Thursday that no vessel is believed to have been in "physical contact" with the children who died.
Emergency services recovered 10 people, all believed to be children, from the water near Bournemouth Pier at roughly 4.30pm on Wednesday.
Dorset Police said the girl and boy sustained “critical injuries”, and later died in hospital while the other eight were treated for injuries that are not life-threatening.
Dorset Police Assistant Chief Constable Rachel Farrell said at a press conference on Thursday: “To avoid further speculation, I am able to tell you that it's clear that yesterday a number of people already in the water got into difficulty and we are investigating the circumstances or event that caused that to happen.
"Early investigation indicates that there was no physical contact between a vessel and any of the swimmers at the time of the incident.
"I can also confirm there is no suggestion of people jumping from the pier or jet-skis being involved."
Eyewitness Trevor Pinto had been walking along Bournemouth Pier with his 16-year-old son on Wednesday afternoon, and said the tragedy happened “very close” by.
He told the BBC they watched as lifeguards attempted to resuscitate two people, adding: “It took me a while to realise, ‘oh my god someone had lost their life’.”
Ritta Saruchera said her daughter and a friend were in the sea at the time when they saw what happened.
She added: “They were coming back out of the water when they saw a teenage boy struggling.
“We went to get help from the lifeguard and inform them of what was happening. There were three young men out there and they have been searching for a fourth.”
Families who have arrived at the beach on Thursday have spoken of their shock at the previous day's events.
One woman, who did not want to be named, said: “It's such a shame, people just come here to have fun during the half term, it's a real tragedy."
Detective Chief Superintendent Neil Corrigan, of Dorset Police, said: “Our thoughts are with the loved ones of the young people who tragically died and we are doing all we can to support their families.
“I understand the beach was very busy at the time of the incident and I would ask anyone with information that may assist our enquiries to please come forward.
“We are at the early stages of our investigation and would ask people not to speculate about the circumstances surrounding the incident."
Bournemouth West MP Conor Burns said the incident was a “salutary lesson" that “danger is ever present" on beaches and the ocean.
“Thoughts with everyone associated with the dreadful events unfolding in Bournemouth this evening," he said.
“A salutary lesson that our beaches and ocean can give much pleasure but danger is ever present.
“Thanks to the Life Guards and the Air Ambulance who we can take for granted."
