It was reported that a man entered the water from a boat in Arne Bay between 8pm and 9pm on Friday, May 29.
However, a police report was not made until two days later at 6.56pm on Sunday, May 31.
Police at Walking Field Lane, Poole on June 1 (Image: NQ)
A Dorset Police investigation is now underway into the circumstances of the man going missing and why the report was made two days later.
The man has still not been found and extensive searches are ongoing to find him.
Three men have since been arrested on suspicion of murder, including a 46-year-old from Poole, a 31-year-old of no fixed abode and a 22-year-old from Essex.
All men remain in police custody.
South West Police Forensics and Dorset Police officers were spotted searching an address in Walking Field Lane in Poole on Monday evening, June 1.
Police at Walking Field Lane, Poole on June 1 (Image: NQ)
One resident, who did not wish to be named, said: “Last night, I came back from a cycle maybe about 10pm.
“I saw there was a police van, maybe three or four police cars and then a whole bunch of police people outside the house.
“They were there until gone midnight. I went to bed at that point.
“Then this morning I see that they’ve got two police people stationed at the front and the back.”
He added: “They were trying to presumably keep it secure.
“Forensics showed up today, probably about 2pm.
“There’s been police coming and going, bits of paper, forms, stuff like that.
“[I have] got no idea what’s going on.”
A spokesperson said: “Dorset Police received a report at 6.56 pm on Sunday 31 May 2026 reporting that a man was believed to have gone into the water from a sailing boat in the area of Arne Bay between around 8 pm and 9 pm on Friday 29 May 2026.
“An investigation is underway into the circumstances of him going missing and the subsequent reporting of the matter two days later.
“His whereabouts remains unknown and detailed searches are being carried out to try and locate him.
“As part of the investigation, three men – a 46-year-old from Poole, a 31-year-old of no fixed abode and a 22-year-old from Essex – have been arrested on suspicion of murder and remain in police custody, with the arrests made to assist the investigation in gathering information and also to provide legal protection to those involved as enquiries continue.
“Officers are working hard to establish a clear picture of what happened and we would urge people to refrain from speculating on the circumstances of this incident as a thorough investigation is carried out into the matter.”