David was reading in his hotel room when he heard a knock at the door and someone trying the door handle. When he opened it, a man he didn't know claimed he was in the wrong room and walked away. David called the front desk to have police called because the man had obviously been trying to steal from his room since he tried opening the locked door without identifying himself first.

1. Stranger Danger 8 th Grade Forensic Science T. Trimpe 2006 http://sciencespot.net/ Case #7 Can you solve it? Daily CSI

2. David was sitting in his hotel room reading a book, when he heard a knock at the door, and the sound of someone trying the door handle. He opened the door, where he saw a man whom he had never seen before. The man said, "I'm terribly sorry ... I thought this was my room. Wrong floor, I guess." He then walked off down the hall toward the elevator. David went back into his room, thought about what had just happened, and then phoned the front desk, suggesting they call the police, since the man at the door had obviously been a thief. Why was David so sure the man had been a thief? Source: http://kids.mysterynet.com/quicksolve/