Vichai Srivaddhanaprabha was in the helicopter when it came down at about 20:30 BST on Saturday.
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.
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”.