Gone girl kidnapping suspect Matthew Muller has confessed about his involvement in the kidnapping of Denise Huskins in an "off the record" interview with a reporter that was secretly recorded by the Federal Bureau of Investigation, according to Wired.

The FBI claims that they were able to catch Muller on tape, saying that he had acted on his own and that his mental illness and a "side-effect from a vaccine" prompted him to do the deed.

The suspect made these comments to a female reporter back in July, FBI Special Agent Wesley Drone said in an affidavit to reinforce a search warrant, the Daily Mail reported.

Muller was arrested back in July in South Lake Tahoe during a home-invasion robbery in the San Francisco Bay Area in relation to the kidnapping case, which was initially deemed a hoax by police because Huskins resurfaced and appeared unharmed a few days after she was abducted.

It all began when Huskins' boyfriend Aaron Quinn reported that kidnappers broke into their home in Vallejo on March 23, kidnapped and held her for an $8,500 ransom.

Muller's arrest came as a shock to his family, friends and relatives, as he was a man with a bright resume and promising future as a lawyer. He was a graduate of Harvard Law School and a member of the bar in the state of California.

He was also a U.S. Marine veteran, but everything came crashing down when was fired from his post as an immigration attorney, filed for bankruptcy and lost his license to practice law over claims that he failed to file a green card application for a client after he took an advanced payment of $1,250.