Acting on a tip off, the Police raid a flat to arrest a suspected muderer. Theydon't know what he looks like, but they know his name and that he is inside the flat. The Police burst in and discover a bricklayer,a Taxi driver, an Electrician and a Fireman all playing cards. Without any hesitation, or communication, they immediately arrest the Fireman.
How do they know they have got the suspected Murderer??
How do they know they have got the suspected Murderer??