Here are some signs of lying and behaviors that will help you tell if someone is telling the truth.
Some people give away signs of lying without even realizing it. These are not as accurate as a lie detector, but here are some possible indications and what to look for:
All of these of course offer no conclusive proof of lying as there are other possible reasons for many of the behaviors or reactions, but the more signs there are the more likely the person is lying.
Reference: (How to detect lies,Bifaloo.com,2005)