LLR Partners, a Philadelphia investment firm which has raised $3 billion from clients including the Pennsylvania state, public school, and Philadelphia city pension funds, among others, says it has purchased 3SI Security Systems, a Malvern firm that tracks stolen cash, drugs, and electronics, and supplies exploding dye packets and anti-explosive automatic-teller protection systems to banks, for an undisclosed sum.

3SI employs around 167 in North America, including 48 at its corporate office and Global GPS Tracking Support Center in Malvern, LLR spokeswoman Kristy DelMuto said.

3SI was spun off by the former Imperial Chemical Industries (ICI) in 2002. At the time, 3CI employed 175 in the U.S. LLR bought the company from Stirling Partners, a British investment firm that paid $93 million in 2006, giving previous owner American Capital Strategies Ltd. a $27 million gain on its four-year investment. As part of Stirling, 3SI bought a string of security tech companies in the U.S., U.K., and western Europe.

LLR cash will help 3Si grow beyond the financial-services and retail markets, 3SI CEO Todd Legett said in a statement. LLR's cofounders include veteran real estate investor and Valley Forge Casino owner Ira Lubert, chairman of the Penn State board of trustees.