MADISON, Wis. -

The 19-year-old who beat a Fitchburg man to death with a baseball bat last November was sentenced Monday.

Koalton Peterson reached a plea deal this summer for a reduced sentence of second-degree reckless homicide and aggravated battery with intent to cause great bodily harm.

Peterson argued with Ryan Smith, of Fitchburg, when Smith met Peterson to buy marijuana, according to a criminal complaint. Smith hit Peterson in the face before Peterson retaliated and fatally beat Smith with a baseball bat.

“I felt lost. I felt like this guy, Koalton, had taken a part of my heart away from me,” said Chelsea Smith, Ryan Smith’s sister.

“Anybody else that has not lost a child, you would not know how that feels. It hurts every day,” said Jeffrey Smith, Ryan Smith’s father.

According to testimony, the fight was all over $10 worth of marijuana.

Peterson was sentenced to 20 years behind bars and 15 additional years of extended supervision.