David Pietz, 34, has been charged with charged with second-degree murder in his wife's death. With Nicole's mother looking on, David Pietz pleaded not guilty in King County Superior Court.
The victim's mother, Gael Schneider, flew in from Arizona for the proceedings.
"We're so glad that they've made an arrest and taken this step forward," she said after seeing her daughter's accused killer in handcuffs.
Ever since Nicole disappeared from the couple's Lynnwood home in 2006, David insisted he was a doting partner and loving spouse.
"(We're) trying to focus on what we can do on finding her so you don't let your mind go to bad places," David told KOMO News shortly after his wife was reported missing.
A few days later, Nicole's naked body was found dumped in a wooded area in Burien.
Investigators said David Pietz was the last person to see his wife alive, and he told police that when he woke up at about 8:20 a.m. on Jan. 28, 2006, his wife had already left.
But forensic evidence showed Nicole Pietz likely died around midnight the morning of Jan. 28 -- a time when David Pietz claimed his wife was asleep in their bed, according to court documents.
David Pietz also failed a polygraph test, and when detectives asked him to retake the test, he refused and hired an attorney.
A search of Nicole Pietz's car, which was found in the University District after her body was discovered, turned up DNA evidence belonging to both David Pietz and his wife, "but Nicole's DNA was in very small quantities, while the defendant's DNA was in much greater quantities," investigators wrote.
The couple had financial problems and the marriage was "in some degree of turmoil," the document said, adding David Pietz had extramarital affairs and tried to get other women to join him and his wife in bed.
Detectives added David Pietz had conducted an Internet search on his computer for swinger's clubs as well as ways to cheat on one's spouse. And just weeks after his wife's death, he began looking for phone numbers of women to date, according to the court documents.
The case went unsolved for more than half a decade until last month, when detectives from the King County Sheriff's Office cold case unit arrested David for investigation of second-degree murder.
Nicole's mother spent the last six years pushing to keep attention focused on her daughter's case.
She traveled from her home in Arizona to attend Wednesday's arraignment, where she joined other friends and relatives who were wearing paper hearts with "Justice for Nici" written on them.
"I've known all along it was him," Schneider said. "I think he deserves an Academy Award, because he sure had us convinced (otherwise). If he does get off, I suggest he goes to Hollywood because he certainly is a good actor."
David Pietz is being held in the King County Jail on $1 million bail.