It’s absolutely insane to think about, but the FBI took an interest in Hudson in 1965.
According to released FBI documents, Hudson was not being directly investigated, but the bureau kept tabs on the actor under suspicion of homosexuality. Apparently an informant said he had an “affair” with the matinee star.
After the 1969 Stonewall Riots in New York City, Hudson was releasing a movie, and the Los Angeles bureau wrote a memo to FBI director Herbert Hoover asking what they had found out about Hudson.
Luckily, those files didn’t go anywhere, and Hudson was left alone. There’s no evidence of his house being under surveillance.