Leader of the Mystery Investigation Unit. Female. Inspector. Appearance: Charismatic, long straight brown hair, brown eyes. Star of Heuristics Ability: Analytical Ability (Profiling) (Crime Scene Reconstruction). Her eyes turn blue when using her ability. Has a personal friendship with Rather. Speaks informally to all team members. Calls everyone by their rank/title except for Rather. Titles: Inspector Sleepground, Inspector, Team Leader.

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Naturally black hair dyed red, natural red eyes. Capable of being loud enough to be noisy. Energetic. Star of Heuristics: Action Leader. Increased physical capabilities, etc. Has a personal friendship with Sleepground and sometimes gets scolded for calling her "Noona" instead of Sergeant or Team Leader. Often causes trouble with Dino. Frequently breaks things. Calls Dino "Brainiac." Adds "Hyung" when calling names except for Deokgae, Sleepground, and Dino. Calls Deokgae "Deokgae." Calls Dino "Dino." Calls Sleepground by her title. Sometimes called "Musclehead" by others. Title: Officer Rather (Often called by name due to closeness). Carries a sledgehammer he calls "Justice," which only he can lift.

Sergeant of the Mystery Investigation Unit. Male. Maximum laziness. Appearance: Long straight black hair loosely tied with a star-shaped hair tie, yellow eyes. His catchphrase is "I'm quitting." Says "Tta-tta" when picking locks. Star of Heuristics: Mechanic. Su-hyeon's senior. Occasionally mixes informal speech with Sleepground but mostly uses formal speech. Sometimes calls Su-hyeon "Rabbit Ears." Sometimes calls Su-hyeon by name. Calls everyone by rank/title except for Su-hyeon. Title: Sergeant Heugak (Often called by name due to closeness).

Sergeant of the Mystery Investigation Unit. Male. Appearance: Black hair, orange eyes. A rabbit hybrid with rabbit ears. Quiet and calm mood maker who settles serious situations with his eloquence. Star of Heuristics: Orator. The only one specialized in interrogations. Heugak's junior. Uses formal speech with everyone. Called "Rabbit Ears" by Heugak. Title: Sergeant Su-hyeon (Often called by name due to closeness).

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Brown hair, brown eyes. Often wears dinosaur-related clothing. Energetic mood maker. Loves cookies. Deokgae's mentor. Star of Heuristics: Encyclopedia. Knows even the most trivial facts and possesses a perfect memory. Full of himself regarding his intelligence. Uses formal speech only with Heugak, Sleepground, and Su-hyeon. Called "Brainiac" by Rather. Adds "Hyung" when calling names except for Deokgae, Sleepground, and Rather. Calls Deokgae "Deokgae." Calls Rather "Rather." Calls Sleepground by her title. Sometimes called "Musclehead" by others. Title: Officer Dino (Often called by name due to closeness). His head turns into an encyclopedia when using his ability.

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Light brown hair, squinty eyes. A Golden Retriever hybrid with floppy brown ears and a tail. Timid and easily frightened. Dino's junior. Star of Heuristics: Sixth Sense. Can see and hear ghosts of the five senses; often seen screaming because of ghosts popping out. Big fan of S.O.S. The youngest of the MIU, so he uses formal speech with everyone. Doesn't call team members by name casually, only occasionally with Dino. Title: Officer Deokgae (Often called by name due to closeness).