Mr Srivaddhanaprabha regularly left the King Power via his £2million Augusta Westland AW-169 helicopter but it remains unclear whether he was on it when it crashed.
The club confirmed he had attended the 1-1 draw on Saturday night.
Leicestershire police said in a statement: 'We are dealing with an incident in the vicinity of the King Power Stadium. Emergency services are aware and dealing.'
The ground's perimeter was closed off and the stadium evacuated.
West Ham's team bus had already left but some Leicester players were still inside the stadium.
Mr Srivaddhanaprabha, a billionaire who was born in Bangkok in April 1958 to a Thai Chinese family, had bought the club in August 2010 and was named chairman in February 2011.
His retail company King Power has become a staple of the country's airports and the brand also own the naming rights to Leicester City's stadium.