Dorset Police attended an incident at 12.57 pm on 9 august, Saturday.
There were reports of concern for the welfare of a man at an address in Edgehill Road in Winton area.
Dorset police attended with ambulance service.
Officers attended and an 88-year-old local man was found dead at the address.
Dorset Police has said a police cordon is currently in place while an investigation is carried out.
One neighbour, who has lived in Winton for more than a decade, said they were shocked to see such a large emergency services presence near their home.
She said: “The police have been here since yesterday afternoon. When we saw so many officers, along with an ambulance and forensics near the house, we didn’t know what had happened.”
Another neighbour said he had been watching emergency services come and go since yesterday.
He said: “There were police everywhere, and an ambulance. Officers have been here all night, with police cars constantly coming and going. I saw a lot of them.”
His next of kin have been informed and they are being kept updated with the progress of the investigation.
Following enquiries, a 60-year-old woman from Bournemouth has been arrested on suspicion of murder and remains in police custody at this time.
She is believed to be known to the deceased man.
Detective Chief Inspector Neil Third, of the Major Crime Investigation Team, said: “Following the discovery of the body, we have launched an investigation to establish the full circumstances surrounding the death, which is currently being treated as unexplained.
“I am keen to speak to anyone who has seen any suspicious activity around the address since Friday 18 July 2025 to please come forward. You may have vital details to help us establish what has happened.
“To enable us to gather as much information as possible about circumstances surrounding the man’s death, and in order to provide legal protection for the individual, we have made an arrest.
“There will be an increased police presence in the area while we work to establish what has happened and we would encourage anyone with information or concerns to please speak with an officer.”
Anyone with information is asked to contact Dorset Police at www.dorset.police.uk or by calling 101, quoting occurrence number 55250117622.