Devon & Cornwall Police say a 26-year-old man was arrested on Friday afternoon at an address in Newton Abbot on suspicion of the murder of Ann Widdecombe.
The suspect, a white British national, is in police custody while inquiries continue, police say.
Assistant Chief Constable Matt Longman says they have set up a public portal where people can share information, and where images or footage can be submitted.
He says officers were called to Widdecombe's home at around 11:40 on 9 July 2026, and she was located deceased in the property with "serious injuries".
Her next of kin have been informed and are being supported, he says.
Police say the incident is not being treated as terrorism after consulting with counter-terror policing as part of "initial inquiries".
Asked if there is any indication the incident was politically motivated, he repeats that the investigation is in its early stages and they remain "open-minded", but adds: "At this time I have got no information to believe that that is a politically motivated crime."
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