Hours after it was reported that the UK tech tycoon Mike Lynch was one of the people missing in Monday’s superyacht sinking off the coast of Sicily, news of a tragic coincidence emerged.

Stephen Chamberlain, 52, Lynch’s former co-defendant in a US fraud trial, in which they were both acquitted, had died in hospital after being hit by a car while jogging in Cambridgeshire.

Like his former boss, Chamberlain had risen to the most senior ranks in the British tech world before his success was overshadowed by the long legal battle related to their time running one of the UK’s most prominent startups.

The collision occurred on Saturday morning on the A1123 Newmarket Road, north of Cambridge. Chamberlain’s lawyer said he had been “fatally struck” by a car while running. He was taken to hospital and put on life support, and his death was announced late on Monday.

Earlier that day the yacht carrying Lynch and 21 others had sunk after reportedly being hit by a waterspout. Lynch’s wife has been rescued but he, his 18-year-old daughter and Morgan Stanley International’s chair, Jonathan Bloomer, are among those missing. The whereabouts of Lynch’s lawyer, Chris Morvillo, and his wife also remains unknown.

The deaths come after Lynch and Chamberlain were cleared in June of US fraud charges that could have resulted in years in prison.

Chamberlain studied mechanical engineering and management at the University of Birmingham before spending a decade as an auditor. In 2005 he joined Autonomy, the startup founded by Lynch that had become one of the champions of the British tech scene.

Lynch had used his mathematical skills, honed in a doctorate at Cambridge, to build a company that specialised in sifting huge amounts of corporate data for useful information. In 2011 the US computing giant HP swooped to take it over.

Chamberlain, under Lynch and the company’s finance chief, Sushovan Hussain, was a key part of the team that saw through the $11bn deal. It was a triumph for Autonomy’s shareholders, but the deal turned sour a year later, shortly after they left the company, when HP alleged “serious accounting improprieties” and knocked $8.8bn off its value.

A US Department of Justice investigation followed and, by 2018, Lynch and Chamberlain were indicted for conspiracy and wire fraud.

Despite their legal troubles, Lynch and Chamberlain did not sit still. Lynch was one of the founders of Darktrace, a cybersecurity company, and he brought in Chamberlain in 2016 to serve as chief financial officer. Chamberlain also volunteered as finance director of the League One football club Cambridge United.

Darktrace, which is now a member of the FTSE 100, has accepted a £4.3bn takeover offer from a US private equity investor. When Chamberlain joined it was worth $200m, according to his LinkedIn profile. The business grew, and Chamberlain was promoted to chief operating officer until September 2020, when he took paid “administrative leave” to face the US charges.

A Darktrace spokesperson said the company was “incredibly saddened” to hear of the death of Chamberlain, “a substantial contributor to the team in its early years”.

They added: “Steve was much loved by his colleagues and leaves many friends at Darktrace. 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.”

Unlike Lynch, who fought an extended battle against extradition, Chamberlain voluntarily surrendered to the US district court. In a sign of their close relationship, Lynch paid Chamberlain’s legal fees.

Hussain had already been jailed after a US jury found him guilty of fraud related to the takeover, and a judge had ruled in favour of HP in a civil fraud case. However, prosecutors struggled to tie the fraud to Lynch and Chamberlain, and both were acquitted on all counts in June.

During the trial, Chamberlain had limited his public statements to a running blog in which he detailed mountain races of up to 100km in Wales and England’s Peak and Lake Districts. After being cleared of the US charges he thanked his lawyers on the LinkedIn social network and wrote: “Acquitted in June 2024 and now looking to help growing companies achieve their goals.”

In a statement released through Cambridgeshire police, Chamberlain’s family said: “Steve 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.

“He made a lasting impression on everyone who had the privilege of knowing him. He will be deeply missed but forever in the hearts of his loved ones.”