A court-appointed armed guard, tasked with ensuring Mike Lynch did not abscond while facing fraud charges, has paid tribute to the tech mogul, saying the security team “became less of a detail and more like a family”.

Rolo Igno also described “the memory of a beautiful soul” in Mr Lynch’s daughter Hannah, 18, after they died in the sinking of the luxury superyacht Bayesian off the coast of Sicily early on Monday.

Mr Lynch founded software giant Autonomy in 1996, and was cleared in June of carrying out a massive fraud relating to its 11 billion dollar (£8.64 billion) sale to US company Hewlett Packard, after a trial at a federal court in San Francisco, California.

Mr Igno said he had the “privilege” of spending “almost every waking moment” with Mr Lynch while he was in custody in San Francisco, describing the detail as unlike any other he had ever worked and one that was “life changing”.

“As an executive protection agent, the number one rule is simple, don’t ever get close to the principal,” he said.

“They aren’t your friends, they’re a client and the relationship is strictly professional. But with Mike, that didn’t fly with him and for me that rule quickly dissolved.”

He told a story about the first time he escorted Mr Lynch and his daughters, Hannah and Esme, to lunch.

“I opened the door for them and told Mike, ‘If you need anything at all sir, I’ll be right at this table by the entrance’,” Mr Igno said.

“He chuckled and in his confident way, Mike replied, ‘No, no, no, you’ll be sitting with us’.

“When I hesitated, not wanting to disrupt their family time, he insisted, saying, ‘Rolo, do you want me to tell my beautiful daughters that the tough and handsome security guy, who was a former marine, didn’t want to sit with us because he was intimidated by them?’ How could I possibly say no to that?

“So, I joined them, sitting at the far end of the table, feeling out of my element but gradually realising how genuine and loving they all were.”

Mike, if you’re listening, I will always have your back. I will forever be here for Angela and Esme

Work started to feel less like work, Mr Igno said, as he described being excited to get back to San Francisco after his days off “just to be around Mike”.

“The year I spent living with him allowed me to experience first hand his loving and caring heart,” he said.

“The security team became less of a detail and more like a family.”

He described their shared time in Ravello, Italy, earlier this month, calling it one of his “most cherished memories”, adding: “Overlooking the stunning Amalfi coast, Mike came up to me and said, ‘Rolo, I feel so much better knowing you will always have my family’s back’.

“He was right, and Mike, if you’re listening, I will always have your back. I will forever be here for Angela and Esme.”

Angela Bacares, Mr Lynch’s wife, was rescued after disaster struck the Bayesian.

“Mike, I will forever cherish our short time together,” Mr Igno said.

“My family will miss your masterful storytelling, and we will forever regret not seeing you do the robot dance that night, we were so close.

“Hannah, my family and I will miss your beautiful smile, your loving soul, and your calming presence. My daughter Emma will never forget the time you two shared.”

He added: “I don’t know what everyone’s beliefs are, but I believe that Mike and Hannah woke up in a far better place.

“Till we see each other again. Hannah, take care of your daddy up there for me. Down here, I’ve got your mum and sister.”

Italian prosecutors have opened a manslaughter and negligent shipwreck investigation, against unknown persons, into the deaths of seven people in the sinking of the Bayesian.

Recaldo Thomas, who was working as a chef on the vessel, with Morgan Stanley International bank chairman Jonathan Bloomer, his wife Judy Bloomer, Clifford Chance lawyer Chris Morvillo and his wife Neda Morvillo, also died in the tragedy.

A press conference was held in the court of the Italian town of Termini Imerese on Saturday, where officials announced the investigation and answered questions from the media on how the yacht sank, why passengers remained on board when others escaped, and what questions the vessel’s crew are facing.

The prosecutor in charge of the case, Raffaele Cammarano, suggested that passengers may not have been able to escape from the yacht because they were asleep, according to a translation.

He said the Bayesian was hit by a downburst, which are powerful winds that descend from a thunderstorm and spread out quickly once they hit the ground.

Mr Thomas’ body was recovered near the scene on Monday and the six others were recovered from inside the wreckage between Wednesday and Friday.

Of the 22 passengers and crew on board, 15 were rescued after escaping on to a lifeboat.

The boat trip was a celebration of Mr Lynch’s acquittal in the fraud case.