ST. LOUIS–(BUSINESS WIRE)–Thompson Street Capital Partners (TSCP), a private equity firm based in St. Louis, Missouri, announced today a growth investment in Karpel Computer Systems, Inc. (“Karpel”), the largest provider of prosecutor case management software for state and local government agencies. Terms of the transaction were not disclosed.
Founded in 1985 and headquartered in St. Louis, Missouri, Karpel provides case management system (CMS) software for prosecutor and public defender offices nationwide. Its flagship platform, PROSECUTORbyKarpel (“PbK”), serves as the system of record for more than 800 prosecutor offices across more than 30 states, managing over 30% of felony prosecution across the country. Karpel’s software enables prosecutors to efficiently execute the full lifecycle of a criminal case, from charging through sentencing, while maintaining secure integrations across law enforcement, courts, and other critical justice system stakeholders.
Jeff Karpel, Founder and CEO of Karpel, said, “For almost three decades, our mission has been to equip prosecutor offices with intuitive, reliable technology that helps them serve their communities efficiently and effectively. We have grown organically by focusing exclusively on the unique needs of prosecutors and delivering a product that our customers rely on every day. We are excited to partner with Thompson Street as our first institutional investor. Their experience scaling founder-led software businesses and investing in mission-critical vertical software platforms makes them an ideal fit for Karpel’s next chapter.”
Craig Albrecht, Managing Director at TSCP, said, “Karpel has established a clear leadership position in a niche, growing public sector software market by focusing on the complex needs of prosecutors. The company’s strong recurring revenue profile, exceptional customer retention, and mission-critical role within regulated criminal justice workflows create a highly defensible foundation for long-term value creation. We look forward to supporting the team as they continue to expand their market presence and invest in product innovation that empowers prosecutors to focus on their core mission of keeping communities safe.”
Tom St. Geme, Managing Director at TSCP, added, “We have been tracking Karpel’s success for several years and have been consistently impressed by the quality of the product and the strength of customer relationships. As governments shift from manual, paper-heavy workflows to digitally native platforms and manage the rapid expansion of digital evidence, Karpel is well positioned to capitalize on these trends. Together, we plan to invest in go-to-market and product enhancement initiatives while pursuing strategic opportunities across the broader criminal justice software ecosystem.”
Raymond James and Lewis Rice served as advisors to Karpel. Sidley Austin LLP served as legal counsel to TSCP.
About Thompson Street Capital Partners
Thompson Street Capital Partners (tscp.com) is a St. Louis-based private equity firm focused on investing in founder-owned middle market businesses in the life sciences and healthcare, software and technology, business and consumer services and products sectors. Founded in 2000, the firm has acquired more than 250 companies and had assets under management of over $4.5 billion as of September 30, 2025. TSCP partners with management teams to increase value by accelerating growth, both organically and via complementary acquisitions.
About Karpel
Karpel Computer Systems is a leading provider of prosecutor and public defender case management software solutions for state and local government agencies. Its flagship product, PROSECUTORbyKarpel (“PbK”), serves more than 800 prosecutor offices nationwide and is designed to manage the full lifecycle of criminal cases with seamless integrations across the justice system. Headquartered in St. Louis, Missouri, Karpel has been serving the public sector since 1995.
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