A former Royal Marine charged with assisting the Hong Kong intelligence service has been found dead, police say. Matthew Trickett, 37, a Home Office immigration officer, appeared in court charged under the National Security Act last week. He was found by a member of the public in a park in Maidenhead, Berkshire on Sunday, Thames Valley Police said. His death is being treated as unexplained and a post-mortem examination will be carried out in due course, the force added. Officers attended Grenfell Park in Maidenhead at around 17:15 BST on Sunday, where Trickett was found. He was given emergency treatment but was pronounced dead at the scene. A black forensics tent could be seen inside a cordoned-off area in the center of the park on Tuesday evening. Police officers were also stationed around the park. Detectives are asking for anyone who was in the park on Sunday afternoon to come forward if they have any information. In a statement, Trickett"s family said they were "mourning the loss of a much-loved son, brother, and family member." "We would be grateful if the press would respect our privacy at this difficult time and refrain from intruding on our grief," they added. His solicitor, Julian Hayes, said: "we are naturally shocked at this news and supporting his family as best as we can". Trickett was a Home Office immigration officer, who had previously served as a Royal Marine for six years. He was also the director of a security firm called MTR Consultancy. Last week, he was charged along with Chi Leung (Peter) Wai, 38, and Chung Biu Yuen, 63, under the National Security Act with assisting the Hong Kong intelligence service and foreign interference. Between 20 December 2023 and 2 May, they are accused of agreeing to undertake information gathering, surveillance and acts of deception that were likely to materially assist a foreign intelligence service. It is also alleged that they forced entry into a UK residence on 1 May. The three accused men spoke only to confirm their identities during their court appearance. They had not yet entered pleas and were granted bail until this Friday, when they were due to appear at the Old Bailey. At last week"s hearing, prosecutor Kashif Malik asked that Trickett be kept in custody for his own welfare as he said the defendant had attempted to take his own life after being charged, but that request was refused and he was granted bail. The force has referred itself to the Independent Office for Police Conduct because it was in contact with Trickett as he was on bail at the time and had to regularly report to a police station. — BBC