Harry Bowman, 46, a lover of the outdoors who doted on his two daughters, had only recently been hired as a statistical analyst for the San Bernardino County Department of Public Health.
For several years, he had been an expert on data sets and mapping for the University of Southern California's National Center for Risk and Economic Analysis of Terrorism Events.
"He was a great guy, very friendly, always willing to help," said Isaac Maya, the center's director of research and transition, who recalled writing a glowing letter of recommendation when Bowman decided to change fields.
"We had a very nice lunch for him at the University Club" when he left, Maya said.
At the center he'd used his expertise in software, mapping and data sets to evaluate the risk and economic impact of terrorist events in order to guide authorities in their planning and decision making.
Bowman, who lived in Upton, was also a dedicated member of the Roman Catholic Church who frequently taught religious classes.
Much of the rest of his free time was spent hiking or visiting with his school-age daughters, whose college education he was saving for.
"This is a tragic loss for our family, much like it is for all families around the world who have experienced this kind of violence," his family said in a statement. "There are no words that express our sadness in losing such a special person."
Bowman was also a native of Pennsylvania, and that state's governor, Tom Wolf, offered his condolences following what he called this "senseless violence."