Mustard is best known as the lead detective on the nationally known Denise Huskins kidnapping case. Vallejo police called it the 'gone girl' case, and mistakenly calling it a hoax. "To think that this is the Officer of the Year, it's an insult," Huskins' attorney Doug Rappaport said.
RELATED: Suspect indicted in Vallejo 'Gone Girl' kidnapping case
Rappaport said it's a slap in the face to his client.
Muller is charged with invading Huskins' and her boyfriend Aaron Quinn's home in March of 2015.
Muller allegedly blindfolded, drugged and threatened the couple before abducting Huskins. A civil complaint said Muller sexually assaulted her, though he hasn't been charged for that crime.
RELATED: Lawyer for Vallejo woman says kidnapping was not hoax
Rappaport said initially Vallejo police suspected Quinn killed Huskins. When she turned up, Vallejo police said the couple made up the kidnapping and sexual assault.
At the investigation's helm - Mustard. "He jumped to conclusions, he blindly went about supporting his conclusions. It was like he got on a plane thinking he was going to go to New York, he got off in Iowa and said, 'wow I never realized there were so many corn fields in Manhattan,'" Rappaport said.
RELATED: Vallejo PD believes kidnapping claim a hoax
Ultimately Dublin police along with federal investigators caught Muller three months later after he left his cellphone behind at a Dublin home invasion.
The following month Vallejo's police chief sent an apology letter to Huskins.
Mustard has been a police officer since 1995 and with VPD since 2001. He also serves as Police Officer Association President.
"He may do a very fine job in other cases and this may be the one time he didn't, but boy when the one time he didn't, it was a big one," Rappaport said.
No one at the Vallejo Police Department including Mustard was available to comment Thursday about the award.
Kidnapping victim's attorney says fam outraged VPD Detective Mat Mustard is Officer of the Year - called crime hoax pic.twitter.com/Iqb1lNjcKY— Melanie Woodrow (@MelanieWoodrow) May 12, 2016