"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.

In an exclusive interview with CBS News California, Huskins and Quinn detail what happened after the documentary ends. They knew Matthew Muller had committed additional crimes, but they say Vallejo police and the FBI refused to investigate.

Law enforcement officials said that Matthew Muller — the man at the center of the Vallejo kidnapping case that was outlined in the Netflix documentary “American Nightmare” — may have committed sexual assault and kidnapping as early as 1993 when he was 16 years old.

Years before Denise Huskins was kidnapped from her Vallejo home, held captive, and accused by police of carrying out a “Gone Girl” inspired hoax, Matthew Muller had other targets, investigators said.

In addition to the "American Nightmare" case and another home invasion, Matthew Muller is now linked to a 1993 kidnapping and sexual assault case, along with two home invasions in 2009 and a 2015 home invasion and kidnapping case.

Matthew Muller, already serving a 40-year sentence in the Denise Huskins case, had been terrorizing the community for two decades before the widely known "American Nightmare" case, prosecutors said.