Lie detection services private investigators and detectives.The service provided reflects the over 30 years of law enforcement the owner has. Desert Polygraph in Las Vegas, NV is suited to meet any of your polygraph examination needs. We offer mobile polygraph services on a 24/7 basis, after work and on weekends. We can come to a suitable location near you to perform polygraph testing. As you know, the polygraph instrument is the oldest and best-known method of determining the truth. All polygraph exams are conducted on a Lafayette LX-4000 or LX-5000 computerized instrument using the latest software.