The helicopter crashed in a ball of flames in the club's car park on Saturday after a Premier League match.
Officials from the club and Vichai's company, duty-free giant King Power International, declined to comment on whether he was in the helicopter when it spiralled out of control and crashed around an hour after the game.
According to eyewitnesses, the helicopter just cleared the top of the stadium before it started to spin. It then plummeted to the ground and burst into flames.
A spokesman for the Midlands club said on Saturday: "We are assisting Leicestershire Police and the emergency services in dealing with a major incident at King Power Stadium."
John Butcher, who was near the stadium at the time of the crash, told the BBC his nephew saw the helicopter spiral out of control apparently due to a faulty rear propeller.
"Within a second it dropped like a stone to the floor...Luckily it did spiral for a little while and everybody sort of ran, sort of scattered. As far as we are aware nobody around the car park was caught up in this problem."
In Thailand, officials at King Power said they could not yet comment on the crash or say whether Vichai had been aboard.
Vichai is a huge favourite with the fans after he bought the unfancied side from central England in 2010 and they went on to stun the football world by winning the league title in 2016.
Leicestershire Police said a team from the Department for Transport's Air Accidents Investigations Branch had taken charge of the investigation into the cause of the crash.
ENGLISH CHAMPIONS
After pumping millions of pounds into the club, he helped steer them back into the top flight in 2014 before they stunned the sport by beating the likes of Manchester United, Liverpool and Chelsea to become champions of England.
Leading players in the side, including Jamie Vardy and Harry Maguire, sent messages of support on Twitter while rival clubs including Manchester City also voiced their concern.
Freelance photographer Ryan Brown was covering the game and saw the helicopter clear the stadium before it crashed, the BBC reported.
"Literally the engine stopped and I turned around, and it made a bit of a whirring noise," Brown told BBC Radio 5 Live. "It turned silent, blades started spinning and then there was a big bang."
Leicester had played a league match at home against West Ham United earlier on Saturday, drawing 1-1.
The self-made businessman Vichai founded Thai duty-free giant King Power in 1989.
The duty-free business got a big boost in 2006 when it was granted an airport monopoly under the government of then prime minister Thaksin Shinawatra, and it continued to prosper even after Thaksin's ouster in a coup that year.
The family's empire also includes Belgian football club, Oud-Heverlee Leuven.