Sentinel Offender Services Pay & Benefits | Glassdoor

Sentinel Offender Services Overview

Irvine, CA
201 to 500 employees
Company - Private
Business Services
$25 to $50 million (USD) per year
Helping people stay on the right path to a better life.

Since 1993, Sentinel Offender Services has been chosen by law enforcement agencies from across the country (i.e., courts, sheriff departments, probation and parole departments, etc.) as a trusted ... Read more

Mission: At Sentinel Offender Services, we are committed to helping create the best possible client management outcomes for our customers and the communities they serve. We demonstrate that commitment by offering high quality electronic monitoring hardware, innovative software platforms ... Read more

Company Updates

  • Sentinel Employees Go All Out for Crittenton Angel Tree Program Sentinel employees came together for our annual support of the Crittenton Services for Children and Families Angel Tree Program and provided Christmas gifts for 100 children of all ages.

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Sentinel Offender Services – Why Work For Us?

About Sentinel Offender Services

Since 1993, Sentinel Offender Services has been a trusted partner of courts, sheriff departments, probation and parole departments, and other law enforcement agencies from across the country. We provide comprehensive case management and offender-management services.

Sentinel pioneered the first participant-funded program model in which all program fees are paid for by the participants directly, saving taxpayers millions of dollars in jail costs. At the time of enrollment into a participant-funded program, Sentinel staff conducts detailed financial assessment on the individual. The results of that assessment are used to establish a suitable daily fee for the participant—based on their ability to pay—that is accordance with the supervising agency’s approved sliding fee schedule. This no-cost approach for the government can be provided for any of the services we offer.

Through these programs, Sentinel has been able to dramatically reduce the cost of expensive supervision for municipalities and their law enforcement agencies—all while operating with strict adherence to the rules, guidelines and oversight of our customers.

Moreover, our success has been built upon our ability to provide superior value through comprehensive, customizable and scalable services that include hardware, software, local community-based personnel and best-in-class 24/7/365 offender monitoring capabilities.

Robert Contestabile

Founder + Chief Executive Officer

Robert Contestabile has more than 30 years experience in the security and monitoring industry. While serving as President of Florida-based Wackenhut Monitoring Services, Mr. Contestabile purchased the company and Sentinel Offender Services was born in 1993. In the intervening years, Mr. Contestabile has grown Sentinel into one of the largest and most successful electronic monitoring companies in the industry with over 225 customers in 48 states.

In that time, Mr. Contestabile has created an extremely successful track record and has become an undisputed leader in a tumultuous and challenging industry. From the very beginning Mr. Contestabile and his team at Sentinel began building a legacy of innovation—starting with the creation of the first offender-funded monitoring program in the nation. In 1993, Sentinel created the inaugural offender-funded monitoring program that required the participant to pay for all of the fees associated with participating in the program—this truly unique model was the first of its kind. Since its inception, Mr. Contestabile has successfully implemented programs like this across the nation, allowing agencies to operate highly-effective and cost-efficient electronic monitoring programs at no cost to the agency or tax payer.

A key to the successes of these programs has been Sentinel’s 24/7/365 National Monitoring Center, a state-of-the-art electronic monitoring facility located in Irvine, California. Mr. Contestabile created this multi-platform hub to offer national and international customers alike numerous agency- and offender-funded monitoring options that include RF, GPS, alcohol and domestic violence monitoring and prevention. A native of Pennsylvania, Mr. Contestabile earned his Electrical Engineering Degree from the University of Pittsburgh. Since relocating, he enjoys spending the mild winters and beautiful summers that southern California has to offer with his wife Gwen and their wonderful grandchildren. An avid golfer, Mr. Contestabile can often be found taking advantage of any number of California’s fine golf courses.

Darryl Martin

Divisional President + Chief Operating Officer

Darryl Martin has more than 25 years of direct experience within the electronic monitoring industry. His prior experience includes eight years with Digital Products Corporation and nine years at Sentinel Offender Services, where he served as Vice President and General Manager. Mr. Martin transitioned his career to G4S Justice Services in 2007 in order to oversee that company’s nationwide monitoring, technical, and internal operations before becoming its president. As Chief Operating Officer, Mr. Martin maintains executive responsibility for the company’s internal, technical and field operations, which includes the company’s network of field offices that specialize in case and offender management programs that are designed to aid program participants.

Mr. Martin is a graduate of Chapman University and received his MBA from the University of Redlands.

Mark Contestabile

Divisional President + Chief Business Development Officer

Mark Contestabile has worked with Sentinel since 1997. He has worked closely with both Sentinel’s Sales and Operations Team to ensure successful set-up, implementation, and daily program operation across the nation. His extensive training and experience led him to his current position as Chief Business Development Officer/Divisional President, where he provides hands-on leadership and shares his vision for the future direction of the company.

Mr. Contestabile graduated from the Terry College of Business at the University of Georgia.

Sentinel Offender Services - Monitoring Center


Why work for the Monitoring Center?

  • Quality Training programs
  • Hands on experience with monitoring equipment and software
  • Opportunity to develop valuable call center skills
  • Relationship building with law enforcement personnel
  • Growth – Tiered Career Progression Program
  • 24/7 environment, 5, 4 and 3 day work shifts
  • Fun recognition programs

Monitoring Center Qualities

Join the Sentinel family to gain knowledge and leadership qualities, in order to succeed and grow within the company. Sentinel looks for individuals with a thirst for knowledge, employees who utilize their resources and ask questions. Employees are encouraged to incorporate new experiences into their guidebooks and find more ways to efficiently work. As a Sentinel employee your work ethic and display of leadership will be acknowledged.

ISO Certified (International Organization for Standardization)

We are proud to be ISO 9001 certified. Sentinel continually improves and complies with the ISO 9001 Standard to enhance customer satisfaction through effective application of a quality management system.  Our quality management system consistently provides products and services that meet customer applicable statutory and regulatory requirements.

Sentinel Offender Services – Field Operations

Sentinel Offender Services is a pioneer in the offender management space. We establish partnerships with our agency customers to build programs that effectively assist with offender behavior modification and reintegration back into the community to stop the cycle of recidivism. Offender Funded Programs offer a more positive and cost effective alternative to jail. In addition, Agency Based Programs provide Case Management, Electronic Monitoring Services, Moral Reconation Therapy (MRT) instructed classes, Substance and Alcohol Monitoring.

Field Office positions                           

Sentinel provides students and graduates a stepping stone in a Criminal Justice career. The following positions provide face-to-face interaction with probationers, contacts with agency/department personnel and case management training.

Case Manager

The Case Manager provides a service to the contracted Department by handling an assigned caseload of offender’s serving an alternative sentence of electronic monitoring, and is primarily responsible for the comprehensive case management and enforcement of restrictions that are ordered by the Court, Probation, Parole, or Sheriff’s Department.

Administrative Assistant

Provide a professional representation and support to the branch office as needed.

Drug Test Technician

Serve Sentinel customers by collecting offender drug tests through followed procedures and notifying officers of results.

Equipment Installer

Responsible for daily client scheduling, inventory control and installing, removing, as well as, troubleshooting equipment.


Below are locations of our customers we serve:

Los Angeles County Sheriff and Probation Department

San Diego Sheriff and Probation Department

Dallas, TX CSCD

D.C. Pre Trial Services

Connecticut DOC

City of Phoenix, AZ                                            

Butte County, CA Sheriff’s                                                          

Leon County, FL Probation

County of Greenville, SC

Kansas DOC

Riverside, CA Sheriff’s Department

Seattle WA, City of Seattle Municipal Court

Employee Spotlight – April 2017

      Sentinel would like to highlight an individual who has shown the progression an employee can achieve at Sentinel Offender Services. We would like to spotlight Paula Guardado.

For over a decade, Paula has risen through the ranks from a Case Manager, to a Branch Manager to her current position. She is responsible for the day to day operations of all of Los Angeles County adult and juvenile programs including the oversight of Sentinel Staff. Los Angeles is a demanding program that requires diligent attention to detail and follow through. Once Paula provided oversight at our Los Angeles location, we have maintained glowing audit reviews from the department.

Paula has been utilized to onboard new employees, train agency personnel and launch new programs throughout the United States. She is always willing to step up and help the organization whenever needed at other, out of state locations. In a few words Paula is DEPENDABLE, PROFESSIONAL and RESPONSIBLE. Thank you Paula!

Sentinel Offender Services Reviews

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Recommend to a friend
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Robert Contestabile
20 Ratings
  • Featured Review

    "Industry Standard"

    • Work/Life Balance
    • Culture & Values
    • Career Opportunities
    • Comp & Benefits
    • Senior Management
    Current Employee - Anonymous Employee in Irvine, CA
    Current Employee - Anonymous Employee in Irvine, CA
    Positive Outlook
    Approves of CEO

    I have been working at Sentinel Offender Services full-time (More than a year)


    Collaborative environment with technology, customer service and administration


    Corporate office needs some upgrade (which is scheduled to start soon)

    Advice to Management

    Take your great ideas and complete the execution of them so the company is able to gain more market share

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Sentinel Offender Services Photos

Sentinel Offender Services photo of: Tracking Devices
Sentinel Offender Services photo of: BBQ 2017
Sentinel Offender Services photo of: BBQ 2017
Sentinel Offender Services photo of: BBQ 2017
Sentinel Offender Services photo of: San Diego Team
Sentinel Offender Services photo of: Holiday Celebration
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Sentinel Offender Services Interviews



Getting an Interview

Getting an Interview





    Financial Representative Interview

    Anonymous Employee in Atlanta, GA
    Accepted Offer
    Positive Experience
    Average Interview


    I applied online. I interviewed at Sentinel Offender Services (Atlanta, GA) in July 2015.


    It was a two to one ratio. It was very nerve wrecking but over all it was ok. After everything was said and done I asked questions about the company as well like -what was the turn over rate and how can I gain from working with the company.

    Interview Questions

    • what do you know about the company, tell us about yourself and what makes you unique?   Answer Question
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Sentinel Offender Services Awards & Accolades

  • Excellence in Employment, Goodwill of Orange County, 2016
  • ISO 9001 Certification, American Systems Registrar, LLC,, 2016

Sentinel Offender Services Locations

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