Gooey Louie

The FBI investigated LOUIE LOUIE lyrics for two years in the 1960s.. and it all started because of a Florida teenager’s letter to Robert Kennedy stating that the lyrics were obscene.. 

The teacher got the lyrics wrong. The FBI never questioned the maker of the song to see what the actual words of the song were. So how much money did the FBI super snoopers spend on investigating this one way back in 1964?