eere Final answer:
The Black Panthers and the Ku Klux Klan were groups outside the government that were said to have hidden communist activities.
Step-by-step explanation:
The groups outside the government that were said to have hidden communist activities were the Black Panthers and the Ku Klux Klan. It is important to note that while the Black Panthers were a leftist revolutionary socialist organization, they did not have any substantial evidence of hidden communist activities. The Red Scare and the McCarthyists were events and individuals associated with the investigation and persecution of alleged communists in the United States.