Sentinel’s management team offers more than 200 years of combined industry experience. This is a rarity in an industry that simply didn’t exist 30 years ago. That amount of experience gives Sentinel a significant advantage when it comes to addressing the complex problems facing the criminal justice system.

Robert Contestabile

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

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

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.

Dennis Fuller

Dennis Fuller

Chief Financial Officer

Sentinel is pleased to welcome Dennis Fuller as the new Chief Financial Officer. In this role, Dennis will oversee all finance and accounting activities for Sentinel Offender Services.

Dennis comes to Sentinel with over 16 years of experience as a financial analyst, controller and, most recently, as the CFO at Search Optics located in San Diego. His knowledge and business acumen have been in high demand as he currently serves on the board of directors for several start-up organizations in southern California. A native of Orange County, Dennis is a graduate of Long Beach State University and earned his MBA with specialization in Finance from Ashford University in Clinton, Iowa.

A former pilot and current drummer in a rock band, his outside interests are as varied as his career in finance has been steady. When not at the office, Dennis spends time with his wife and two children in Carlsbad where he can be found helping to coach youth football and, like so many of us, chasing a small white ball around any of the many of the beautiful golf courses here in southern California.

Glen Huang

Glen Huang

Vice President of Information Technology

Glen Huang is Vice President of Information Technology for Sentinel Offender Services. In this role, Mr. Huang is heads Sentinel’s IT Division and is responsible for the technical development and strategic direction for all of Sentinel’s software applications, networks and infrastructure. This includes a substantial focus on IT security, redundancy and data preservation.
Mr. Huang brings an impressive portfolio of technical accomplishments and has held a number of technology-focused senior level management positions thus far in his career. Prior to joining Sentinel, Mr. Huang served as an IT and software consultant for Alorica, where he gained extensive exposure to the after-sales services sector. His role included designing and integrating SAP- ERP and Oracle-based CRM and warehouse management software (WMS) solutions to improve service functionality and performance. Before that, he led consulting projects encompassing hardware infrastructure design, construction, deployment and integration at Neutron Technologies and later NEC, with a focus on SAP and Oracle applications in large and medium-sized companies.
While working at Goodwill Industries, Mr. Huang developed a specialized keyboard for the sight impaired. He began his career at the Gemological Institute of America, where he designed a computer-based program in Oracle to grade diamonds more efficiently.

Mr. Huang earned his Bachelor of Science degree in Business Administration and Computer Science from the University of Southern California and earned his Master of Business Administration from University of College London Devonshire. In addition, he is a certified Project Management Professional (PMP), is a Microsoft Certified Trainer and System Engineer (MCT/MCSE) and is a Six Sigma Black Belt.

Melissa Starr

Melissa Starr

Vice President Field Operations

Melissa Starr began her career in the electronic monitoring industry in 1997 with Sentinel Offender Services managing an active offender caseload of 150 clients in Los Angeles County. She was quickly promoted through the Company to Branch Manager, Project Director and then Field Operations Manager of the Western Region where she was responsible for all branch operations and business development in the Western United States. In 2014, Ms. Starr was promoted to Vice President of Field Operations. She is responsible for contract retention, ensuring adherence with strict SOP’s and expanding our spectrum of services with current customers. As a true industry veteran, her expertise in relationship building with customers and consulting towards “best practices” has resulted in a contract retention rate of over 95% in a very volatile and competitive industry.

She is a graduate of Chapman University with a Bachelor of Arts in Criminal Justice and is a member of the Association of Women Executives in Corrections.

Chris McDowell

Chris McDowell

Director of Marketing and Communications

Chris McDowell has spent the majority of his career supporting the efforts of highly functioning—and highly successful—sales organizations. He brings considerable experience in helping sales organizations become even more successful by leveraging his deep understanding of technology and considerable marketing acumen.
As the Director of Marketing for Sentinel, Mr. McDowell is responsible for developing and implementing strategic marketing initiatives that will enhance the organization's sales efforts. His primary focus at Sentinel is on generating new revenue from existing customers through client engagement; recruiting new customers by increasing brand awareness in the marketplace, and; using technology to create greater efficiency in the execution of marketing programs while increasing ROI and reducing costs.

Mr. McDowell received his Bachelor of Arts Degree from George Mason University where he was captain and two-time national champion with Mason's skeet and trap team.

Julie Hunt

Julie Hunt

Director of Human Resources

Julie Hunt is responsible for implementing human resource management strategies that enable Sentinel to recruit, train, and retain a high performing and motivated workforce. Hunt specializes in talent management, staffing, employee benefits, learning and development. She also oversees personnel requirements mandated by our government contracts with correctional agencies nationwide and makes sure we continuously meet or exceed them. She has been a member of the Sentinel Offender Services team since the company’s founding in 1993.