SAN DIEGO (AP) — J. Robert Beyster, who founded a small technology firm called Science Applications International Corp. and built it into one of the largest defense contractors in the United States, has died at age 90.

Beyster's family says the engineer-turned-entrepreneur died Monday of natural causes at his San Diego home.

Beyster, who held a doctorate in physics, founded SAIC in 1969 with a handful of employees.

Before it was spun off into two companies last year, it had $11 billion in annual revenues and 44,000 employees. The current SAIC has 13,000 employees.

Beyster said he founded his own company after deciding the U.S. government wasn't getting its money's worth from other defense contractors.

SAIC was founded as an employee-owned business. It became publicly traded in 2006.