The Rocklin Police Department has identified the victim in Saturday's stabbing homicide.
Robert Earl Vickney Jr., a 51-year-old resident of Rocklin, was stabbed to death at his home in the 6200 block of Swan Court, where a party was being held in the backyard.
Vickney was stabbed once in the chest. He was taken to Sutter Roseville Medical Center, where he was pronounced dead.
Additional witnesses are being interviewed and detectives are investigating the incident.
This is the first homicide in the city in six years, and police arrested Zachary Raymond Kachmar, 20, of Rocklin. He was taken to Placer County Jail, where he is being held without bail.
Investigators determined that Kachmar and Vickney had argued at the party, and Kachmar allegedly pulled out a pocket knife and stabbed Vickney once.
Kachmar knew the victim's son, according to Rocklin police Capt. Lon Milka.
It was not known Sunday what the argument was about, but police have recovered the knife.