The Michigan Court of Appeals upheld the conviction of Keith Lintz, who was found guilty of murdering Niles couple John and Carolyn Tarwacki in February of 2010.

A Cass County jury found the Niles man guilty of two counts of first-degree murder in November 2013. Lintz was later sentenced to life in prison without the possibility of parole.

Lintz’s lawyers argued earlier this month in appeals court that the prosecution made errors during the trial and that Lintz had ineffective assistance from his defense attorney during the trial.

After hearing the arguments, the appeals court ruled this week that there were “no errors warranting relief” from the conviction.

Cass County Prosecutor Victor Fitz said his office and the Office of the Attorney General are pleased with the court of appeals’ decision.

“The bottom line is that through the efforts of (special prosecutor) Doug Baker and the prosecution team a murderer is off the streets,” Fitz said.

The Tarwackis were found murdered in their home on Carberry Road in Howard Township on Feb. 5, 2010. Both were stabbed and shot multiple times.

Although Lintz was interviewed early on in the investigation, he was not arrested until more than two years later in October 2012.

Although there was no physical evidence tying Lintz to the scene of the crime, several witnesses testified during trial that Lintz admitted to them he was responsible.

The guilty verdict was based largely on the testimony of those witnesses and other circumstantial evidence.

Lintz maintained his innocence during his sentencing hearing, saying to the Tarwacki family, “I’m sorry for your loss, but I didn’t do it. That’s all there is to it.”

Fitz said Lintz could appeal the decision to the Michigan Supreme Court.