🦊 Detective 180

The case

Gajju Haathi, the owner of Step Street, discovered that an expensive pair of red-and-gold shoes had disappeared from his store. The security camera had captured Jakku Siyar wearing the missing shoes. In the photograph, Jakku's right arm was covered by a red cast. When Gajju confronted him, Jakku denied stealing the shoes. "That cannot be me," Jakku said. "My left arm is injured." Gajju called Detective Lomdi. She looked at Jakku, examined the security photograph and immediately knew that he was lying.

Your question

How did Detective Lomdi know who was lying?