Former U.D. student was watching World Cup final when explosions killed 64 people.
A California-based aid group says its worker who was killed in the Uganda explosions had attended the University of Delaware.
Invisible Children of San Diego, which strives to end the use of child soldiers, identified the dead American as Nate Henn.
Henn was among at least 64 people killed when explosions tore through crowds watching the World Cup final at a rugby club and an Ethiopian restaurant. Police feared an al-Qaida-linked Somali militant group was behind the attacks.
According to the aid group, Henn studied psychology at the University of Delaware, where he also played rugby.
Jason Vanterpool, who played rugby with Henn, says Henn got along with everyone and was always smiling.