Czech billionaire Petr Kellner has died in a helicopter accident in Alaska, along with four others.
The accident happened on 27 March, with his company PPF saying it was being investigated by the National Transportation Safety Board.
Kellner and his group had been on a heli-skiing trip, which involves off-trail, downhill skiing or snowboarding reached by helicopter instead of a ski lift
So, who was the billionaire, what is known about the crash and how has he been remembered?
Who was Petr Kellner?
The 56-year-old was the richest man in the Czech republic, worth an estimated $17.5 billion (£12.7 billion).
He was born in Czechoslovakia in May 1964 and grew up in the city of Liberec, Czech Republic.
In 1986, he graduated from the University of Economics, Prague Faculty of Industrial Economics.
Kellner founded investment fund PPF in 1991. The company was successful from early on and purchased stock of more than 200 corporations with nominal value 5 billion CZK.
The investor went to use his stakes in the fund to buy a controlling stake in the country's largest insurance company.
In 2010 he bought a Boeing 737-700 BBJ1 as his business airplane and resided in a large mansion in the village of Podkozí near Prague.
His wealth continued to grow as he invested in real estate all over the world, as well as owning one of the largest collections of photographs taken by well known Czech photographer, Josef Sudek.
In August 2016, Kellner was named by Forbes as #102 wealthiest people in the world, with an estimated $11.4 billion wealth, making him the wealthiest person in the Czech Republic.
Last year, he bought major European broadcast network, Central European Media Enterprises, for $1.1bn.
In 2021, he ranked 68th in the world’s rich list, with an estimated $17.4 billion estimated wealth.
At the time of his death he was married to Renáta Kellnerová - his second wife - and leaves behind four children.
What happened in the helicopter accident?
Officials reported that the crash took place in unknown circumstances about 50 miles east of the Alaskan city of Anchorage at 6.35pm on Saturday 27 March.
The five others who died were named as Gregory Harms, 52, of Colorado; Benjamin Larochaix, 50, also of the Czech Republic; and two Alaskans, Sean McMannany, 38, of Girdwood, and the pilot, Zachary Russel, 33, of Anchorage.
Alaska State Troopers said a sixth person on board was in a serious but stable condition on Sunday at an Anchorage hospital.
They added that they became aware of the crash following reports of an overdue helicopter and possible crash debris on the mountain, on Saturday evening.
The five passengers included three guests and two guides from Tordrillo Mountain Lodge, company spokesperson Mary Ann Pruitt said.
Mr Harms was a pioneering heli-ski guide in Alaska and worked for many years at the lodge. His ski-company has led many trips across the world.
"Greg was one of the most experienced guides in the business," Ms Pruitt told the Associated Press.
Mr McMannany was a guide for over a decade and had spent the past five at the lodge. He was also an avalanche instructor and an experienced mountain guide on Denali, North America's tallest peak.
Mr Kellner and Mr Larochaix "were loyal and frequent" guests at the lodge according to Ms Priutt.
Mr Russel was a pilot for Soloy Helicopters, a Wasilla-based company that is contracted by the lodge to provide transportation, Ms Pruitt said.
The lodge released a statement in which it told how it had never “had to face an event of this measure" in its 17 years of hosting guests.
"This news is devastating to our staff, the community in which we operate, and the families of the deceased,” the statement said.
How have others paid tribute to Kellner?
Kellner’s company, PPF, led tributes with a statement on its website which read: “His professional life was known for his incredible work ethic and creativity, but his private life belonged to his family.
“His funeral will be held with only close family members. We please ask the media to respect the privacy of the Kellner family during this difficult time.
“We want to express our gratitude for the condolences, well wishes, and prayers expressed so far to the bereaved.”
Kellner, who was also a former co-owner of Czech soccer club Slavia Prague, was remembered by the team. A Twitter post from the club read: "Slavia would like to offer its deepest and most sincere condolences to the family and friends of Mr. Kellner."
Czech prime minister Andrej Babis described it as “an unbelievable tragedy.” He offered his condolences to the family and told how he was “terribly sorry about it.”
The family have not released a statement and it is unlikely that they will as Kellner led a private life and rarely engaged with the media.