The Leicester City owner’s helicopter crashed in a car park outside the club’s ground as it left the stadium following a Premier League match.
Vichai Srivaddhanaprabha was in the helicopter when it came down on Saturday, a source close to the family has told the BBC.
One witness said he saw Leicester player Kasper Schmeichel run out of the stadium towards the scene of the crash.
It is not known how many other people were on board the helicopter.
Leicester had drawn 1-1 against West Ham United at the King Power Stadium.
The game kicked off at 17:30 and finished about one hour before the helicopter took off.
Under Mr Srivaddhanaprabha’s ownership, Leicester City won the Premier League in 2016, having started the season as 5,000/1 outsiders.
Thai billionaire Vichai Srivaddhanaprabha purchased Leicester City in 2010
One Leicester season ticker holder, who did not wish to be named, said: “I saw Kasper Schmeichel run out first [from the stadium] and then loads of security guards and stewards.
“I was stood outside the ground but it crashed on the other side.”
Another witness said it appeared “the tail propeller wasn’t working, putting it into a spin”.
‘I have seen staff in tears’ – Reaction to Leicester helicopter crash
In the early hours of Sunday, Leicestershire Fire and Rescue Service’s Assistant Chief Fire Officer Andrew Brodie tweeted that he had just left “multiagency strategic meetings” at Leicestershire Police’s HQ.
He described the crash as “clearly serious and tragic”, he also cautioned people against speculating on cause or who may be involved.
He told BBC Radio Leicester: “The engine stopped and I turned round and it made a bit of a whirring noise, like a grinding noise.
“The helicopter just went silent, I turned round and it was just spinning, out of control. And then there was a big bang and then [a] big fireball.”
Leo Bruka told 5 Live that he saw two police officers whose car was near the crash scene.
“One of them was looking for something and the other one, he ran straight away to the helicopter and he was trying to break the window,” he said.
“Then there is an explosion and they pulled back because the fire was too hot.”
Leicestershire Police said officers were working alongside the other emergency services, the Air Accidents Investigation Branch (AAIB) and Leicester City FC to establish the circumstances of the collision.
In the early hours of Sunday the force tweeted that the AAIB, which said it had sent a team to the stadium, was leading the investigation.
Leicester City said the club was assisting police and emergency services and would issue a more detailed statement in due course.
A Leicester City spokesman said: “We are assisting Leicestershire Police and the emergency services in dealing with a major incident at King Power Stadium. The Club will issue a more detailed statement once further information has been established.”
— Leicester City (@LCFC) October 27, 2018
I have seen staff, backroom staff and [the] first team in tears here his evening. The reception area is described as silent, people looking around and crying and not knowing what to do and consoling each other.
I remember the owners taking over. I said hello to them in native tongue, their face lit up. I have generated relationships with them, seen them in Thailand in Bangkok in their home surrounding, they are really nice people.
With you Leicester City ?#YNWA ?? pic.twitter.com/VrwlWHG4Rm
— Liverpool FC Africa (@AfricaLiverpool) October 27, 2018
The chairman looked at me today on the way to the executive box and said “hello and good afternoon”.We were keeping a close eye on him because of the nature of today’s game and it is really eerie around Leicester at the minute this evening.
Fans and clubs around the world have send their heartfelt messages to the fans and club , in the incident described as horrible
We join the rest of the football community in sending our thoughts and prayers to all those affected following the terrible tragedy at Leicester City tonight.
— AS Roma English (@ASRomaEN) October 27, 2018
The thoughts of all at West Ham United are with everybody at Leicester City at this time.
— West Ham United (@WestHamUtd) October 27, 2018
The thoughts of everyone at Liverpool Football Club are with Leicester City and those affected by events at the King Power Stadium this evening.
— Liverpool FC (@LFC) October 27, 2018
The thoughts of everyone at Rovers are with Leicester City and those affected by events at the King Power Stadium this evening.
We would also like to send our best wishes to Glenn Hoddle, and condolences to the friends and family of the Brighton fan who sadly passed away today.
— Blackburn Rovers (@Rovers) October 27, 2018
My thoughts and prayers are with everyone at Leicester City, horrific pictures on the news, I pray everyone is ok. I can confirm everyone from WHU has safely left the stadium.
— Lady Karren Brady (@karren_brady) October 27, 2018
That was the most difficult @BBCMOTD I’ve ever hosted. Thoughts are with everyone at Leicester City. A terrible tragedy. Heartbreaking.
— Gary Lineker (@GaryLineker) October 27, 2018