If you want to catch someone in a lie, you’ll raise your odds in the afternoon because most people are more likely to cheat or lie then, as opposed to in the morning

The researchers also found that people who tend to cheat regularly were just as likely to do so in the morning as in the afternoon. It was the more ethical folks who suffered lapses as the day wore on

via We Are More Likely to Lie in the Afternoon: Scientific American Podcast.