Court documents show that a missing Massachusetts man wanted in the fatal stabbing of a 76-year-old college professor was charged with brutally slicing a neighbor about five years ago.

Greenfield District Court files say 24-year-old Tyler Hagmaier admitted there were sufficient facts to convict him of assault and battery with a dangerous weapon for the 2011 knife attack on his 41-year-old neighbor in Montague. He was sentenced to probation.

Police have been searching for Hagmaier since Friday, when his car was found near the Connecticut River in Gill. Investigators believe Hagmaier jumped into the river, but there's been no sign of him.

Police believe Hagmaier stabbed Vibeke Rasmussen, a Quincy College professor and his neighbor, more than 30 times before her death. Rasmussen's body was discovered on Friday.