Liam Shields has been charged in relation to alleged offences between February and May 2019 and in May 2022.
Lincolnshire Police said the 24-year-old, who was based in Stamford, had been suspended from duty and the matter had been referred to the Independent Office for Police Conduct.
Assistant Chief Constable Kerrin Wilson said the force took “such allegations very seriously as we know they can affect the confidence of our communities”.
“I would like to offer reassurance that we will always investigate reports like these without fear or favour,” he added.
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