Mario was relaxing in his hotel room in La Galaxy. He heard a knock at the door when he saw a man in the suit whom he never met in his life. The man said "I am very sorry, I thought this was my room" and he left the room. Mario instantly called the hotel manager and ask him to arrest the person.
What made Mario suspicious of the man?
Mario was suspicious of the man as one never knocks its own door at the hotel.