A 21-year-old St. Cloud man is in jail after police say he threatened his 10-year-old sister with a knife. It happened Monday evening on the 700 block of Wilson Avenue Southeast, on St. Cloud’s near east side. Police say Cory Adam Grabuski threatened his sister with a knife and struck a TV several times with a hammer. The girl was not hurt. The suspect was arrested and faces charges of assault and property damage. He’s currently in the Sherburne County Jail awaiting his first court appearance.