LONDON Stephen Chamberlain, once Mike Lynch's co-defendant in the US fraud trial over the sale of Autonomy to Hewlett-Packard, has died after a road accident, his lawyer said on Monday, days before Lynch went missing off the coast of Sicily.

Chamberlain, Autonomy's former vice president of finance alongside chief executive Lynch, was hit by a car in Cambridgeshire on Saturday morning and had been placed on life support, a person familiar with the matter told Reuters earlier on Monday.

Chamberlain's lawyer, Gary Lincenberg, who described him as a "dear client and friend", said he had died after being "fatally struck" by a car while out for a run.

Cambridgeshire Police on Tuesday confirmed the 52-year-old had died. They said the car's 49-year-old driver had remained at the scene and was assisting with enquiries.

Chamberlain's family said he was a much-loved husband, father, son, brother and friend.

"He was an amazing individual whose only goal in life was to help others in any way possible," they said in a statement.

Lynch was one of six people reported missing early on Monday after a luxury yacht was struck by an unexpectedly violent storm and sank off Sicily.

Chamberlain faced the same charges of fraud and conspiracy as his former boss for allegedly scheming to inflate the value of Autonomy, then Britain's largest software firm, before it was sold.

Both men were acquitted of all 15 charges by a jury in San Francisco in June.

After leaving Autonomy in 2012, Chamberlain worked as chief operating officer for Darktrace, the cyber security company that was backed by Lynch's Invoke venture capital fund.

A Darktrace spokesperson said the company was saddened to hear of the demise of Chamberlain, who had been "a substantial contributor to the team in its early years".

"Steve was much loved by his colleagues and leaves many friends at Darktrace," the spokesperson said.

"We extend our deepest condolences to his wife, Karen, and the rest of his family who are very much in our thoughts at this challenging time."

Chamberlain also volunteered as a finance director for Cambridge United soccer club, according to his LinkedIn profile.

"He was a courageous man with unparalleled integrity, and we deeply miss him," Lincenberg said. "He fought successfully to clear his good name, which lives on through his wonderful family." 

  - Reuters