The death of an ex-Royal Marine accused of assisting the Hong Kong intelligence service is not being treated as suspicious, police said.

Matthew Trickett, 37, an immigration enforcement officer and private investigator from Maidenhead, Berkshire, was also accused of foreign interference and had appeared at Westminster Magistrates’ Court with two other people last week.

Thames Valley Police (TVP) said Mr Trickett was found dead in Grenfell Park, Maidenhead, at around 5.15pm on Sunday after a report from a member of the public.

The force confirmed on Friday that, following a Home Office post-mortem completed on Wednesday, the death is not being treated as suspicious.

A spokesperson also said Mr Trickett’s family are being supported by specialist officers.

Mr Trickett appeared at Westminster Magistrates’ Court alongside co-defendants Chi (Peter) Leung Wai and Chung Biu Yuen on May 13.

At that hearing, the prosecution had asked for Mr Trickett to be remanded in custody for his own welfare ahead of his next hearing at the Old Bailey.

However, he was granted bail and on May 19 he was found dead in Grenfell Park.

At a hearing at the Old Bailey on Friday, prosecutor Alistair Richardson said the Crown Prosecution had notified the court that the case against Mr Trickett would be formally “discontinued”.

He said: “As has widely been reported, Matthew Trickett died on May 19 this year. The cause of his death is currently given as unexplained. His death has been confirmed by the coroner.”

He also asked for the formal revocation of Mr Trickett’s electronic tag.

Thames Valley Police (TVP) referred itself to the Independent Office for Police Conduct (IOPC) because Mr Trickett’s bail condition required him to regularly register at a police station.

The IOPC has assessed that referral and decided the matter should be investigated by TVP’s professional standards department.

Mr Trickett was formerly employed by the UK Border Force at Heathrow Airport, before joining Home Office Immigration Enforcement on February 21 2024.

He was also the director of MTR Consultancy, a security firm formed in April 2021.