A Missouri judge has found a 19-year-old Kansas City man guilty of stabbing his grandmother to death a day after she celebrated her 70th birthday.

Corey Barrett was convicted Monday in Jackson County Circuit Court of second-degree murder, first-degree robbery, first-degree burglary and two counts of armed criminal action.

Prosecutors say he killed Marise Barrett in March 2013. A deputy Jackson County medical examiner testified during the bench trial that the victim was stabbed 32 times.

The Kansas City Star reports Barrett initially was charged as a juvenile because he was 16 at the time, but he was later certified to stand trial as an adult.

A 20-year-old co-defendant has pleaded guilty and is being sentenced Friday.

BlakeDavidTaylo, ThinkStock