March 31, 2015 7:40 am Prom Day Fatal Stabbing Suspect to Plead Insanity Christopher Plaskon, charged with stabbing his classmate to death on prom day, is expected to use an insanity defense in a pre-trial hearing Tuesday. US & World Videos 1:42 Car sent flying into the air after speeding through rotary in Massachusetts 0:28 A Vermont state trooper plunges into icy pond to rescue 8-year-old girl 2:59 Keep these travel etiquette tips in mind this holiday season 2:31 Synchronized swimmers: See an incredible triple whale breach 2:20 Bodies of Missing Men Found in Rubber Bins Inside Storage Unit