Wayne Couzens, 48, was locally named yesterday as the officer arrested on suspicion of murder and kidnap in connection with the case.
A married dad-of-two, he is a member of the elite Parliamentary and Diplomatic Protection squad – which entitles him to carry a firearm and a Metropolitan Police warrant card.
It is understood PC Couzens worked a 2pm to 8pm relief shift last Wednesday at the US Embassy in Nine Elms, south-west London.
But Scotland Yard said he was not on duty at the time Ms Everard, a 33-year-old marketing executive, went missing.
At a press conference last night, Met Police commissioner Dame Cressida Dick confirmed ‘human remains’ had been found in an area of woodland in Ashford, Kent.
She added: ‘We are not able to confirm any identity. That may take some considerable time.’
The officer, who has not yet been named officially by the Met, was further arrested for a separate allegation of indecent exposure.
A woman, in her 30s, was arrested at the same address in Kent on suspicion of assisting an offender. Both remain in custody at a London police station.
Dame Cressida added: ‘The news today that it was a Metropolitan Police officer who was arrested on suspicion of Sarah’s murder has sent shockwaves and anger through the public and through the Met.
‘I speak on behalf of all my colleagues when I say that we are utterly appalled at this dreadful, dreadful news.
‘Our job, is to patrol the streets and to protect people. The investigation is large, it’s very fast moving, extremely determined. We have had and continue to have hundreds of officers and staff working around the clock.
‘Sarah’s disappearance in these awful and wicked circumstances I know are every family’s worst nightmare.
‘Londoners will want to know that it is thankfully incredibly rare for a woman to be abducted from our streets, but I completely under that despite that, women in London and the wider public – perhaps particularly those in the area where Sarah went missing – will be worried and may be feeling scared.’
A neighbour said a police officer lives at the address in Deal with his ‘chatty’ wife and two children, adding: ‘They just seemed like a normal, regular family, there was nothing strange about them at all.’
Multiple cars were seen being taken away from the property in Freemens Way, while a neighbour said police were digging up the garden.
A metal fence was also put up surrounding the front garden and driveway.
Another said: ‘You don’t expect it to be on your doorstep, really. You see this sort of thing every day on the TV and the news but you don’t expect it.’
The Met said the investigation is continuing ‘at speed’, with more than 750 households in south London visited and 120 calls received from the public.