Along with the owner's daughter, two pilots and an unidentified fifth person were also on board.
An eye witness told Sky that a helicopter took off from the pitch at around 20:30pm, minutes after Leicester's draw with West Ham on Saturday of the Foxes 1-1 draw with West Ham on Saturday.
The chopper was seen spiralling out of control in the air and crashed in the car park 200 yards away just minutes later.
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.”
Dreadful news regarding the helicopter crash and ensuing fire outside Leicester City's King Power Stadium.— 999 News Emergency 🚨 (@999herts) October 27, 2018
🙏 that the occupants somehow are OK
Pictures from Sky Sports News pic.twitter.com/agHgyAZnWZ
Absolutely chilling footage of BT Sport filming and joking just seconds before Leicester owner’s helicopter crashed this evening...
Absolutely chilling footage of BT Sport filming and joking just seconds before Leicester owner’s helicopter crashed this evening... 😳pic.twitter.com/Fi7sZn1xz2— 999 News Emergency 🚨 (@999herts) October 27, 2018
Under his ownership, Leicester won the Premier League title in the 2015-16 season.
He famously went on to gift each player a £100,000 BMW i8 as a gift for the triumph.
His wife Stephanie, 50, said: "We are both in shock on our way home. It happened straight in front of us as we were leaving the ground.
"We don't know what has happened. It's horrendous. We need to know if everyone is OK. That's the biggest thing. We just hope that everyone got out OK."
BBC football commentator Ian Stringer said the helicopter was "spiralling", and that eyewitnesses said it "came down like a stone".
He said: "I've seen the backroom staff of the first team in tears, the reception area is silent with people just crying."
Several of the Leicester players such as Jamie Vardy, Harry Maguire, James Maddison, Ben Chilwell and Wildred Ndidi, took to social media after the incident to tweet their prayers for those onboard.
🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼— Jamie Vardy (@vardy7) October 27, 2018
🙏🙏🙏🙏🙏🙏🙏— Harry Maguire (@HarryMaguire93) October 27, 2018
🙏🏾🙏🏾🙏🏾— Ndidi Wilfred (@Ndidi25) October 27, 2018
🙏🙏🙏🙏🙏— James Maddison (@Madders10) October 27, 2018
Emergency Services are currently dealing with the incident.
An Air Accident Investigation Branch and Leicester City Football Club to establish the exact circumstances of the collision.