Delaware Attorney General Beau Biden told CNN Radio the indictment is based on "video and digital evidence" seized from Bradley's home and medical practice in December. Authorities have not ruled out additional charges, he added.
"The reality is that as a prosecutor, the rules prohibit me from telling you exactly how I feel -- and I'm feeling a great deal today," Biden said.
Bradley also has medical licenses in Pennsylvania, New Jersey and Florida. Authorities have said they have contacted officials in those states.
He was initially arrested and charged in December.
Bradley's attorney, Eugene Maurer Jr., said he would base his client's defense on
"Most of the evidence in this case comes from videotapes -- it's kind of hard to argue with videotapes," Maurer said, adding, "The issue in this case is going to come down to his mental health at the time."
Biden said Bradley will be arraigned within four to six weeks.
What do you think of all this?