Unlikely Suspects is a single player game that combines a hidden object game with elements of the board game Guess Who?
The game starts with the player being assigned a murder case by their boss, the Head of Interpol, from there the player heads off to look at the crime scene which, like all locations has two hidden object scenes to investigate. As a result of this investigation four clues will emerge, these are places the victim visited shortly before their demise, the player uses these on the map screen to decide which places to visit next.
During the investigation the coroner will pop up with additional clues such as the killer had long hair or the murder weapon was a gun, witness statements will also be received some of which are helpful and some of which are of no use whatsoever. As each piece of evidence comes in the player can go to the weapon screen and identify or eliminate possible options, they do the same with the suspect screen too. Eventually the player will have uncovered three pieces of evidence and their boss will tell them to identify their suspect and make an accusation. It is only necessary for the player to identify the killer and the weapon, they have two attempts to do this - if both are incorrect the trail goes cold and the killer walks free.
When four cases have been solved the player unlocks the Quick Play mode option on the main menu. Each scene visited contains two hidden police badges, when fifty of these have been collected additional game modes in the Detective School are unlocked.