He was a fellow communist. In Honolulu at that time, early 1960’s, probably every communist in town knew all the other communists in town.
Formerly,
The real smart Commies ordered their dumber colleagues to make a big show about "Joining The Party," and becoming "Card Carrying Communists," while they the REAL commies, did not, but concentrated on getting government jobs, focusing on Intelligence Agencies and the State Department.
That's why they were able to throw the CIA, FBI, and Joe McCarthy no end of low-level sacrificial lambs, while effectively keeping the big boys in place.