Navin, 29, is accused of murdering his parents, Jeanette and Jeffrey Navin of Easton, in 2015 and burying them in the yard of a Weston home.
He was arrested in October 2015 and charged with two counts of murder and murder under special circumstances.
His plea came about 20 minutes after Superior Court Judge Robert Devlin rejected all suppression motions by his attorneys.
When making his plea, the judge asked Navin if he agreed with the prosecutor's statement of how he killed his parents and he replied: "More or less."
Prosecutor Michael DeJoseph said that Navin would spend 55 years in prison for the crime.
"It's an ongoing case, so I can't comment more at this time," he said.
Navin is scheduled to be sentenced June 29, DeJospeh said.
Navin graduated from Weston High School and was living in Bridgeport at the time of his parents' deaths. His parents had been reported missing a couple months before their bodies were discovered, and police said that they had a strained relationship with their son, who had financial problems and a history of drug addiction.
Navin's girlfriend, 31-year-old Jennifer Valiante of Westport, was also charged with conspiracy to commit murder and hindering prosecution in the case. In November she pleaded guilty under the Alford Doctrine, meaning that she does not admit guilt but concedes that she would be found guilty under the evidence.
The judge in Valiante's case indicated that he would impose a sentence of 16 years, suspended after she serves eight, followed by eight years of supervised release. She will be sentenced once Navin's case is resolved.
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