Simplify the following text for a Grade 10 native English-speaking person.
Original: Contrary to the Warren Commission , the United States House Select Committee on Assassinations ( HSCA ) in 1979 concluded that President John F. Kennedy was probably assassinated as a result of a conspiracy .
Simplified: Another investigation , by the United States House Select Committee on Assassinations ( HSCA ) in 1979 , found that President John F. Kennedy was probably killed as a result of a conspiracy ( a secret plot ) .