FBI Why doesn't the FBI divulge the types of drugs the Virginia Tech Killer was on?

Will the FBI divulge the type of drugs, and miligrams the killer at Virginia Tech was taking, and why is this information not immediately available to the public? Can the victims seak reperations from the drug companies? I say this because the next day there were articles about antidepressants from the drug companies saying these cl of drugs were perfectly safe useing statics.