However, Alameda County District Attorney Nancy O'Malley declined to discuss any possible target of her investigation, saying it could end with no charges being filed.
"We will ultimately have to make a determination whether the facts support criminal charges and whether those facts can be proven beyond reasonable doubt in a court of law," O'Malley said during a packed news conference at her Oakland office.
Six students were killed last week, including five from Ireland, and seven others were injured when a balcony broke from the side of a Berkeley apartment building.