Ezra Collig, chief of the Bayport police force, is a tall, husky man well known to Fenton Hardy and his sons. Chief Collig often turns to the private detective for help solving particularly difficult cases.
Patrolman Con Riley is a member of the Bayport police force.
Probably the most annoying character in a Hardy Boys book, Smuff is a short, stout man who always wears a checkered suit and soft felt hat. He fancies himself a private detective but is often shown up by Frank and Joe despite his scorn for the two young detectives. In fact, Smuff often falls flat on his face while attempting to prove his worth as an investigator. (Before the books were revised, Smuff, along with Con Riley, was an inept detective with the Bayport police force.)
Fenton Hardy's able operative. Sam and his wife, Ethel, live in an apartment in the center of town, about a half a mile from the Hardy home.
Lean-faced and tanned, Jack Wayne is Fenton Hardy's pilot on all his chartered flights. His plane is called the Skyhappy Sal.