Anderson, 16, "lost her mother and her brother, which she was not aware of until she was recovered in Idaho. She didn't know," Sheriff Bill Gore said Monday morning.
James Lee DiMaggio is suspected of killing the girl's mother Christina Anderson, 44, and brother, Ethan, 8, by setting his house near San Diego on fire Aug. 3. He also is believed to have kidnapped the 16-year-old Hannah with whom he had an "unusual infatuation," police said.
DiMaggio was killed during a rescue attempt Saturday in the Idaho wilderness after a couple spotted him and Hannah earlier in the week. Hannah was taken to a hospital after being rescued.
Gore said DiMaggio fired at least one shot at officers attempting to rescue Anderson.
The FBI will continue the investigation that led to DiMaggio's death, the news website U-T San Diego said.
DiMaggio had a "close platonic relationship" with Christine Anderson, sheriff's officials said.
Relatives were waiting to hear about the events that occurred the night Christine Anderson and Ethan died and the Hannah was taken captive by DiMaggio, NBC News said.
"We don't know what she saw or heard. Hannah is the only person who knows what happened that night," Ralph Britt, husband of Hannah Anderson's grandmother, said on NBC's "Today."
After her rescue, Hannah's father, Brett Anderson, told CNN via text message, "It's now healing time.
Before the reunion, Brett Anderson told Fox News Channel he was "ecstatic that my daughter and I will soon be reunited."
"I'm worried about what my daughter has been put through," he said.
Authorities said the girl did not appear to have significant physical injuries.
During the Fox News interview, Anderson praised law enforcement officials for the rescue.
"They did an excellent job and I can never show my appreciation enough to anybody out there that showed us love and support -- terrific country, love you guys."
DiMaggio was killed during a confrontation near Morehead Lake, Idaho, about 70 miles north of Boise, and a few miles from where DiMaggio and Hannah were spotted Wednesday, officials said.
The shooting happened shortly after FBI teams observed DiMaggio and Hannah separated for a moment.
At that moment, authorities rushed in, took Hannah and ushered her to an area where a helicopter whisked her away, authorities said.
A confrontation then began between agents and DiMaggio, San Diego County Sheriff Bill Gore said. The confrontation ended when an FBI tactical agent shot and killed the murder and kidnapping suspect.
"Obviously we would have liked for Mr. DiMaggio to surrender and face justice in the court of law," Gore said. "But that's not going to be the case."
The rescue and killing ended a tense, multistate manhunt that began Aug. 4, when firefighters found the bodies of Hannah's mother and younger brother at DiMaggio's burning home, east of San Diego.
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