Hypothetical: The Federal Bureau of Investigation (FBI) suspected that Mr Johns was accessing and storing child pornographic materials to his personal computer. Mr Johns, an adult, resided at his parents house. He was not present at home and the FBI obtained the consent of Mr Johns father to search the house and any computers located in the home. The FBI, using sophisticated software, was able to access files on Mr Johns personal computer that was password protected. Mr Johns had password protected his computer and files without his father's knowledge. Mr Johns was convicted of possession of child pornography. He appealed his conviction, which the appeals court upheld.

Question: Did the FBI need a search warrant to search the home and personal computer of Mr Johns? Does password protection deny legal access to the computer by the FBI? Does the consent from Mr Johns' father authorize the FBI to conduct the search and seize the content on Mr Johns' computer? Explain why or why not, citing the appropriate law or case(s) to support your position.