There are some exceptional liars out there. They can sneak their way into a job interview with fake resumes and, when a hiring manager isn't careful, can land themselves impressive positions by providing fake references. These deceitful job applicants are not easy to spot, regardless of how many techniques you use. Sometimes they raise a common red flag, but other times, they do very well at covering their tracks.
Perhaps the best way to flush out a fraud is to talk to them face-to-face. From there, you could ask them many questions and try to catch them in a lie, but as this video from TED-Ed shows, you may just need to watch and listen carefully to how they phrase their responses.