Tom Teves, Alex's father, confirmed his son's death to ABC News. A message left for Tom Teves by the Denver Post has not been returned.
Friends of Teves, 24, began posting on social media Friday night after learning Teves was among the 12 people killed in the Aurora movie theater shootings.
A friend, identified only as Caitlin on Twitter, posted messages on the social media network early Friday from the Century 16 theater, and wrote on Twitter early Saturday that Teves was, "One of the best men I ever knew. The world isn't as good a place without him." She also described Teves as a fan of the University of Arizona and Spider-Man.
An email message to Caitlin has not been returned.
A University of Denver spokeswoman said Teves, from Phoenix, Ariz., graduated in June. The University officially notified its students and faculty of Teves' death Saturday afternoon.
(Copyright 2012 The Denver Post)