LA CROSSE, Wis. -

A La Crosse man convicting of robbing and beating a teenager last summer has been sentenced to six years in prison and five years extended supervision.

Justin Purdy, 21, pleads guilty to robbing an 18-year-old at the Onalaska Skate Park last July, then pistol-whipping the victim 20-30 times.

At his sentencing Wednesday, Purdy apologized for what happened. But La Crosse County Circuit Court Judge Elliot Levine says the crime is part of a bigger problem.

"The problem is this, it's more than just, we made a bad choice," Judge Levine said. "It's a thought pattern that says this is ok, this is how you operate, this is how you do, when you're trapped you lash out."

Purdy had previously served time for a robbery at Ranison's Ice Cream Shop in 2009. He was out only a short time when he robbed and beat the teenager.