Matthew Muller, who is currently serving a 40-year sentence for the kidnapping of Denise Huskins, pled guilty Friday in Santa Clara County court on new charges of medicating and then sexually assaulting another woman.

Matthew Muller was convicted of kidnapping and sexual assault in a 2015 case in which Vallejo police initially accused the victim and her boyfriend of making up the story of her abduction. He pleaded guilty this week in two additional cases.

Muller was in prison for the infamous Vallejo kidnapping when he implicated himself in unsolved attacks in Palo Alto and Mountain View, prompting a renewed investigation and DNA analysis.

"American Nightmare" victims Denise Huskins and Aaron Quinn worked with two small-town law enforcement officials to get kidnapper Matthew Muller to confess to more cold case crimes.

Matthew Muller, featured in the Netflix documentary 'American Nightmare,' was charged with another home invasion in the Bay Area, the second time in recent weeks that new crimes have been attributed to the convicted kidnapper.

Convicted "American Nightmare" kidnapper and rapist Matthew Muller pleaded guilty on Friday to new assault charges stemming back from 2009. Muller was responsible for the 2015 kidnapping and sexual assault of a Northern California woman.

Matthew Muller pleads guilty to invading woman's homes in Mountain View and Palo Alto in 2009, six years before kidnapping Denise Huskins in Vallejo in ordeal initially deemed a hoax.