Greater Manchester's Deputy Chief Constable Ian Hopkins has tweeted:
My thoughts very much with the family and colleagues of @gmpolice PC Gareth Francis after the shocking news of his death.
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Patchy rain affects northern areas of the UK in the next 24 hours. Elsewhere, dry but rather cloudy.
Marjorie and Micheal Cawdery, both 83, were found dead in their house in Portadown, Northern Ireland on Friday.
Ann Myatt, who is contesting Jo Cox's former seat, told a hustings: "We've not yet shot anybody so that's wonderful."