A full inquest into the death of a British-based Russian whistleblower will get under way later amid allegations he was poisoned with sorrel soup.
Alexander Perepilichnyy, 44, collapsed and died while running near his home in Weybridge, Surrey, in November 2012.
The businessman's death was originally attributed to natural causes, but traces of a chemical that can be found in the poisonous plant Gelsemium elegans were later found in his stomach.
A pre-inquest hearing heard that Mr Perepilichnyy had been helping a specialist investment firm uncover a 230 million US dollar (£150 million) Russian money-laundering operation.
Hermitage Capital Management has previously claimed that Mr Perepilichnyy could have been killed deliberately for helping it uncover the scam involving Russian officials.
Coroner Nicholas Hilliard QC will preside over the inquest which is expected to go on for four weeks at the Old Bailey.
At the last hearing, a lawyer suggested the victim may have dined on a popular Russian dish based on the sorrel herb, which could have been poisoned.
Bob Moxon Browne, QC, for Legal and General Assurance Society, queried why no one appeared to have asked Mr Perepilichnyy's widow what he had for lunch that day.
He said: "If he was murdered, it does seem likely he was poisoned rather any other method of bringing about his death."
He suggested Special Branch had been "keeping tabs" on the victim's movements as he frequently travelled by train in the months before his death.
The court also heard Mr Perepilichnyy received threats from an organised crime group and had taken out "multiple" life insurance policies before his death.
Henrietta Hill QC, for Hermitage, said: "There is an issue why Mr Perepilichnyy had so much life insurance. It has been suggested at one point he was advised to take out multiple policies by his bank manager."
Last November, Home Secretary Amber Rudd won a High Court order preventing the disclosure of ''sensitive material'' at the inquest.
The coroner reviewed the secret material and a "form of words" was agreed with the Government.
It stated: "Nothing in the material that was subject to the Public Interest Immunity (PII) application materially assists the coroner in answering the question of how Alexander Perepilichnyy died.
"Nothing in the material alters the decision on scope."
Surrey Police, the family of Mr Perepilichnyy, and the Government will also be represented by lawyers at the inquest.