Case 005
The case
Champa Chachi was waiting for her appointment at Smile Dentistry. When the receptionist called her name, she left her seat for just a moment. Upon returning, she discovered that her purse was missing. "I saw Billu sitting near my purse," Champa Chachi told Detective Lomdi. "I believe he stole it." Detective Lomdi visited Billu's house and questioned him. "I am innocent!" Billu insisted. "I have never visited Smile Dentistry—not today or at any other time." Detective Lomdi carefully examined the room. Within 180 seconds, she knew that Billu was lying.
Your question
What evidence proved that Billu had visited Smile Dentistry?