Police have been given more time to question the husband of a guest house owner on suspicion of her murder.
Joanna Brown, 46, who runs a bed and breakfast in Ascot, Berkshire, was reported missing on Monday morning.
Officers held her husband Robert Brown, at his home in Winkfield, after examining her guest house, which borders Windsor Great Park.
Police are still searching for Mrs Brown and have been given an extra 36 hours to question her husband.
A family member raised the alarm after failing to contact Mrs Brown.
A search of the property, which was empty, led police to believe Mrs Brown may have come to harm.
Officers later received more information and her husband was arrested at his home.
Searches of both properties are continuing.
Det Ch Insp Steve Tolmie, of Thames Valley Police, said: "Family liaison officers have been appointed to provide support to the Brown family and at this time they have indicated that they will not be making any public comment.
"My main priority is to find Joanna and deal with the man we currently have in police custody.
"I appreciate that people in the community may want to know more about the circumstances, and I will provide as much information as I can as soon as there are any significant developments."
The mock-Tudor guest house is described on its website as "a beautiful English country home".