ROCKLIN (CBS13) – Rocklin police are investigating the city’s first homicide in six years.

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“All our neighborhood here are good people, and we are always happy, I’m just shocked,” said neighbor Said Kazimi.

Just after 10 p.m. Saturday, officers responded to the 6200 block of Swan Court to reports of a stabbing.

A 51-year-old man was found inside the home bleeding from his chest. He transported by ambulance to Sutter Roseville Medical Center where he was later pronounced dead.

“He’s a really nice guy, really nice. His girlfriend is a preschool teacher at my daughter’s school,” said neighbor Erica Burriss.

So never would she and her husband imagine soon after moving to the suburbs their neighbor would be killed.

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“There was some kind of physical altercation that occurred between the victim and the suspect,” said Rocklin police Lt. James Knox.

Detectives say an argument during a party at the home between the victim and 20-year-old Zachary Raymond Kachmar lead to a physical altercation in which the man was stabbed in the chest with a pocketknife. Police say Kachmar is friends with the victim’s son.

According to his Facebook page, Kachmar grew up in Rocklin and attended Whitney High School.

Kachmar was arrested for murder and booked into Placer County Jail. He is being held without bail.

This is Rocklin’s first homicide since 2007.

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The victim’s name has not been released at this time.