1971 February 10

Larry Higby, an assistant to Haldeman, tells Butterfield that the president wants an audio taping system in the Oval Office and on White House telephones.

Butterfield works with the Secret Service to install hidden microphones in the Oval Office and on White House phones.

(Butterfield later testifies that the existence of the system is known only to himself, the president, Haldeman, Erhlichman, Higby and the Secret Service technicians.)