Mark A. Contestabile

Sentinel Offender Services LLC provides offender supervision products and services. Its products include voice verification, RF, GPS, and alcohol monitoring, and product data sheets. The firms services include sentinel monitoring, sentinel comprehensive management, sentinel centurion kiosk, substance abuse testing, and financial and reporting services. The company was founded by Robert A. Contestabile in 1993 and is headquartered in Irvine, CA.

Sentinel Offender Holdings LLC provides offender-management services to courts, sheriff departments, probation and parole departments, and other law enforcement agencies. The company is headquartered in Irvine, CA.