A man who received more prison time because he stabbed his girlfriend to death with her 14-year-old son nearby must be resentenced because although the teen was in the house, he didn't see or hear the slaying, the Minnesota Supreme Court has ruled.

In an 11-page order published Thursday, the court found that one of the "aggravating factors" underpinning an upward departure in Raymond Clyde Robideau's sentence for second-degree intentional murder was not accurate.

The ruling reversed a state Court of Appeals decision that said the 38-year sentence -- eight years longer than presumed by state sentencing guidelines -- was justified.

An Anoka County jury convicted Robideau of killing his girlfriend, Sharon Chouinard, in their East Bethel home in January 2008 following a domestic dispute. Her 14-year-old son was in his basement bedroom. He discovered his mother's body in her bedroom the next morning. Police arrested Robideau after he tried to commit suicide by triggering an explosion at a nearby house.

The upward departure in Robideau's sentence was based on two aggravating factors: that the killing was particularly cruel and that it was committed in the presence of a child.

Robideau requested a new trial or a reduced sentence. The Appeals Court affirmed the District Court's departure, saying in part that Robideau "essentially committed the offense in the presence of a child" because he knew it was highly likely the teen would discover the body.

However, the Supreme Court concluded that the aggravating factor was meant to cover situations "where the child sees, hears or otherwise witnesses some portion" of the crime. The Supreme Court ordered that Robideau be resentenced in Anoka County District Court.

Abby Simons • 612-673-4921