You feel uneasy. Some of the things he's said don't make sense. His stories have a lot of inconsistencies, and you can definitely tell that something is off. Here are some ways to tell he's lying to you:

1. He pauses before answering

Former CIA officers list this as the No. 1 red flag when detecting a lie. It means that he's trying to think of an excuse. Even if he already has an alibi made up, his brain still has to remember all the details of the excuse before he can tell you his lie.

2. He covers his face

There's a reason that Pinocchio's nose grew each time he told a lie — when you aren't telling the truth, you can see it in your face. If he puts his hand over his mouth, covers his eyes or rubs his nose a lot while telling you a story, he is probably trying to, quite literally, cover up his lie.

3. He won't make eye contact

This is a universal sign of shame. He doesn't want to confess what he's done, so he's trying to avoid talking about it. Refusing to make eye contact creates a disconnect in the conversation.

4. He's sweating

If his brow becomes a lot more damp than normal when he's telling you something, he's probably telling you a lie. Sweating is one of the first signs of nervousness.

5. Things don't match up

Everyone is a little forgetful sometimes, but if his stories frequently don't line up, then watch out. If his timeline for how late he was out last night doesn't fit with the text messages he was sending you, then you might want to ask some more questions. If he retells a story very differently than the first time he told you, then he might have been making one of them up. Liars can't pull off their deceptions 100 percent of the time, so if you notice frequent mistakes in what he's telling you, then he's hiding something.

6. He gets defensive

He doesn't want you to keep investigating further, so he gets angry when you keep asking questions.

7. He provides way too much information

He's trying too hard to make sure that his lie checks out. This is overcompensation — trying to convince you to believe him.

8. He starts fidgeting

Whether it's shuffling his feet or picking at something, these nervous habits are a dead giveaway.

9. He doesn't answer your questions

He might change the subject, tell you a long story, or he might start asking you questions instead. But he never gives you a straightforward answer.

10. His voice or personality changes

You know him well. If you're asking him questions and he suddenly changes his normal tone of voice, his behavior or his attitude, then this could be a sign of lying. Gregg McCrary, a retired FBI criminal profiler, says, "If his manner shifts abruptly — going from calm to agitated or lively to mellow — chances are he's not telling the truth."