She said the shooting had been an accident and the stranger had run into the woods after shooting her son.
The deputies found Weiker's statement inconsistent, according to Dwes Hutson, Douglas County Sheriff's Office spokesman.
Hutson told The Oregonian Weiker eventually told authorities that her boyfriend, Allen, who had shot her son. She also told police it was accidental and she had gone to a ranger station for help.
Hutson would not say how the .22-caliber pistol went off, but said one shot was fired.
Police are still searching for Allen and warn that he is potentially armed.