A court in the US heard that former New York police officer Gilberto Valle had discussed cannibalism with a British man on an obscene fetish website.
British nurse Dale Bolinger said after he was arrested that he had written "stupid things" online because it was "funny" and his involvement was "fantasy".
Kent police said the sex offence charges against Bolinger came after a joint investigation between UK and US officers.
The charges follow an extensive Kent Police investigation into alleged conspiracy offences in both the UK and the USA.
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It is the fifth publicly known guilty plea in the probe into possible collusion between the Trump campaign and Russia during the election.
Louella Eve Fletcher-Michie, daughter of Holby City actor John Mitchie, died last year at the Bestival music festival in Dorset.
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