Four men Tom, Bill, John & Harry go to the sauna every Sunday.
Tom brings a newspaper to read.
Bill has a thermos with his favorite drink.
John just likes to sit and think &
Harry talks about his career in art, though nobody really listens to him.
All four men are generally distracted in their own business.
One Sunday, John is found dead in the sauna.
Police were called immediately, and no man left the building.
John was apparently stabbed in the chest, but no weapons were found hidden in the sauna.
All three men were searched, but no weapons were found.
One among the remaining three men had to be the killer.
Who did it, and how?