NILES, Mich. -- It was a shocking and grizzly crime that rocked the small town of Niles. John and Carolyn Tarwacki were described as a nice couple, with no enemies and no criminal history.

Two and a half years ago, the couple was murdered in their home in Howard Township, just East of Niles.

Now, for the first time since that deadly winter day, a lead has emerged that has cracked the case wide open.

Police arrested Keith Lintz Wednesday.

Wednesday John Tarwacki Sr. told ABC 57 this is a difficult time for the family, but they are happy an arrest has been made.

The couple worked for the music education company Quinlan and Fabish. February 5, 2010, the couple had a business meeting, but never arrived. Police found the couple murdered inside their home off Carberry Road after family members became concerned that the couple had not shown up for work.

The couple's mastiff, Wrigley, was found unharmed and locked in the bathroom. Police said the intruder came and went through the back door of the home. The weapons used in the murders were never identified by police.

One of the only clues left behind by the killer were tracks in the snow.  

At the time, family members suspected the person may have known the pair because there appeared to be no evidence that the dog tried to stop the killer from entering the house.

Now, Keith Lintz is behind bars for the double murder. ABC 57 talked to the Lintz family, who said an acquaintance recently told police Lintz admitted to killing the couple.

However, the Lintz family said they do not believe Lintz is capable of hurting anyone and believe he is innocent.

This content requires the latest Adobe Flash Player and a browser with JavaScript enabled. Click here for a free download of the latest Adobe Flash Player.