A sister who did not want her name published told the Chicago Tribune a brother flew to Colorado and was notified that John Larimer, 27, was dead. She said another brother was flying to the family's home in Crystal Lake, Ill., this weekend but flew to Denver instead after learning Larimer might be among the victims.
The family was also visited by a Navy notification team, the sister said.
A gunman opened fire in a movie theater early Friday during a midnight showing of "The Dark Knight Rises." Police arrested James Holmes, 24.
Larimer joined the Navy last year and has been stationed at Buckley Air Force Base in Colorado since October.
"I am incredibly saddened by the loss of Petty Officer John Larimer -- he was an outstanding shipmate," Larimer's commanding officer, Cmdr. Jeffrey Jakuboski, said in a statement. "A valued member of our Navy team, he will be missed by all who knew him. My heart goes out to John's family, friends and loved ones, as well as to all victims of this horrible tragedy."