The CSI Process

Critical Solutions International (CSI) is a company made up of exceptional people who have a demonstrable record of transforming challenging problems into thoughtful and affordable engineered solutions. Our expertise working in the Defense, Security, and Applied Research & Development markets allows Critical Solutions International to deliver high-quality solutions to our worldwide clients.

Founded in 1999, CSI provides platforms that detect and mitigate evolving threats for security forces worldwide. When your critical infrastructure is in environments where threats are dynamic and enemies have no border or uniforms, CSI has combat proven solutions that:

  • – Detect and analyze threats
  • – Mitigate threats with multiple platforms
  • – Train and support in-theater personnel to sustain operations and discover future threats
Critical Solutions International
Value Proposition

Based on CSI’s people (experience & contacts) in the Department of Defense, Research & Development and Program Management we posses a combination of skill sets that delivers solutions to our clients most pressing problems.

  • Discover Need
    or Problem
  • Design
    • Current Inventory
    • Research & Development
    • Industry Partners
  • Develop
    • Presenting Solution
    • Extensive Contacts
    • Market SME
  • Deliver Solutions
    • Training
    • Service Support
    • Maintenance & Spares

CSI Overview

CSI Senior Leadership

Patrick Callahan

Chief Executive Officer

Patrick T. Callahan MBA, MA, MS

Patrick Callahan is the Chief Executive Officer of Critical Solution International ( and serves as a member of CSI’s Board of Directors. For three years prior, Patrick served as CSI’s Chief Strategic Officer, responsible for CSI’s strategic growth, business development and research and development operations. Before joining CSI, Patrick was the Director of Business Development for the Survivability Division of QinetiQ North America where he was responsible for managing contracts, proposals and sales totaling over $800 million.

Patrick has over 14 years of documented leadership experience and success in military, educational and business environments. For the past seven years Mr. Callahan has served in several senior management positions in the defense industry and has tremendous success in building business units, driving new business development and providing direction for program management. He has a wealth of experience in leadership, administration and management of personnel, fiscal management, scheduling/planning and problem solving. Mr. Callahan received his B.A. from Cornell University in Ithaca NY, M.A. and M.S. from Simmons College in Boston MA, and his M.B.A. from Babson College in Wellesley MA.

Along with his business experience, Patrick served as an Infantry officer in the United States Army (active and reserve) from 2002 to 2012. From October 2003 until December 2004 Mr. Callahan deployed to Operation Iraqi Freedom with the US Army’s first Stryker Brigade Combat Team and served as a Platoon Leader, Executive Officer, and Company Commander in 1-23 Infantry “Tomahawks”. In addition to his service in Iraq, Patrick led an Escort Platoon and conducted over 300 burial and ceremonial missions in the military district of Washington DC and Arlington National Cemetery as a member of the oldest active Infantry Regiment in the US Army, 1-3 Infantry “The Old Guard”. Mr. Callahan finished his military career after a successful Company Command in the oldest reserve Infantry Battalion in the US Army, 1-181 Infantry.

Patrick is also currently a Visiting Instructor of Leadership at the Citadel’s School of Business Administration. His wife, Kristen, works at the Ashley Hall School in downtown Charleston as the Director of the Intermediate School and Varsity Lacrosse coach. Their daughter, Maisie, is also a student at Ashley Hall. The family enjoys time at the beach, working in the garden, watching the Red Sox, Patriots & Bruins win championships and playing with Riggs, their Chocolate Lab.


  • M.B.A., F.W. Olin Graduate School of Business at Babson College, 2013
  • M.A., Teaching, Simmons College, 2008
  • M.S., Educational Leadership and Administration, Simmons College, 2008
  • B.A., History and Anthropology, Cornell University, 2002


Chief Operating Officer

Stewart A. Thomason MBA

Stewart is the Chief Operating Officer for Critical Solutions International responsible for all program management and business operations. Stewart joined CSI in 2013 to lead the program management activities for the Husky and intelligent surveillance product lines before taking on the COO role.

Prior to joining CSI, Stewart worked for Earl Energy, an off-grid energy solution provider as the head of their military and government business unit. Previously, he spent five years with Force Protection Industries where he served as the Senior Program Manager for the Cougar vehicle program—a $5B urgent acquisition. He also spent two years in Kuwait where he managed Force Protection’s 500+ personnel Middle East operations.

Stewart holds a B.S. in Management from the Unites States Air Force Academy and a M.B.A. from The Citadel. He served in the Air Force as a communications officer for five years, where he attained the rank of captain.


  • M.B.A. from The Citadel
  • B.S. in Management from the Unites States Air Force Academy


Chief Strategy Officer

Heather R. M. Schoetz

Heather Schoetz is the Chief Strategic Officer of Critical Solutions International (

Heather is responsible for creating, communicating and executing strategic initiatives to increase sales. She directs the marketing, business development and research and development efforts at CSI.

Heather recently returned to CSI from Afghanistan where she served in a Security Force Assistance role working for the North Atlantic Treaty Organization-led International Security Assistance Force in Kabul. In this capacity, she was the Director of Sustainment Strategic Initiatives. Her team was responsible for developing, supporting and facilitating Afghan-led initiatives focused on growing capability and capacity in sustainment and logistics.

Heather joined CSI from General Dynamics Land Systems (GDLS), where she served as the Manager of Business Planning and Strategy reporting to the Vice President. Prior to GDLS, she served in various highly visible project management roles valued at up to one billion dollars in the Defense and Security Industry and directly supporting Urgent Operational Needs for two conflicts in Iraq and Afghanistan.

Heather holds a business degree from Wake Forest University in North Carolina. Her team’s efforts in Afghanistan were honored with a Secretary of Defense Award for Excellence in Maintenance Training, Advice and Assistance of Foreign Security Forces.

She resides in Charleston, South Carolina, and can be reached at


Chief Financial Officer

John P. Mei MS, C.P.A.

John Mei is the Chief Financial Officer of Critical Solution International ( Before joining CSI, John was the Chief Financial Officer for Channel Technologies Group, a specialty manufacturer of ceramics used in the Defense and Medical Markets. Prior to Channel Technologies, Mr. Mei was the Chief Financial Officer of Defense Venture Group, a manufacturer of armored vehicles, transparent ceramic armor and run flat tire inserts.

John has over 23 years of financial experience spanning military and defense hardware, electronics manufacturing and software development, and printing industries. Over the last 13 years, Mr. Mei has served as the Chief Financial Officer for several private equity portfolio companies, primarily in the defense industry. He has guided the restructuring of businesses including both equity and debt and has also successfully managed the sale of portfolio companies. Mr. Mei began his career with the public accounting firm of Coopers & Lybrand, LLC and then General Electric in the Industrial Systems and Controls Division. Mr. Mei received his B.S. and M.S. from the University of Massachusetts in Amherst, MA.

Since moving to the South, John has become an avid hunter. His wife, Saysha, volunteers at both Crowders Creek Elementary School and Oakridge Middle School in Lake Wylie, SC. Saysha is the PTA president at Oakridge Middle. Their daughter, Dezirae, is a student at Oakridge Middle and their son Jake is a student at Crowders Creek. Their daughter Celeste was born in the fall of 2014. The family spends much of their time at soccer, swim and track meets that Dezirae and Jake participate in.


  • M.S. Accounting, University of Massachusetts, 1991
  • B.S., University of Massachusetts, 1987

Board of Directors

Andrew Byrd, CEO & President, TVV Capital
Patrick Callahan, CEO, CSI
Raymond Craig III, CSI
Ed Fearon, Vice Chairman, CSI
Matthew Harrison, Operating Partner, Sentinel Capital Partners
Paul Murphy, Partner, Sentinel Capital Partners
Marc A. Buan, Vice President, Sentinel Partners
Ken Weaver, Operating Partner