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A 23-year-old man who plowed his pickup truck into a troop of Girl Scouts picking up trash on the side of a Wisconsin road, killing three girls and one woman, was sentenced Wednesday to 54 years in prison.

Colten Treu pleaded no contest in December to four counts of homicide by intoxicated use of a vehicle and guilty to one count of hit and run causing bodily harm. He had originally pleaded not guilty to all charges.

On Wednesday, he addressed the families of his victims.

"I screwed up bad. No matter what I say or do, you guys are never going to know how sorry I really am," Treu said, according to NBC affiliate WEAU. "I can't give back what I have taken. I want to. Lord knows I want to."

A judge ordered that Treu's 54 years in prison be followed by 45 years of extended supervision. He has been credited 495 days for time served.

Colten Treu. via KARE

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In November 2018, Treu was driving a black Ford F-150 pickup truck north on a highway in Lake Hallie when it crossed over a lane and into a ditch where the troop was volunteering.

He killed Jayna Kelley, 9, Autum Helgeson, 10, Haylee J. Hickle, 10, and her mother, Sara Jo Schneider, 32, according to the Lake Hallie Police Department. Another 10-year-old girl was critically injured.

Police said the group of 12 was wearing highly visible safety vests and was not on the shoulder of the road.

Treu fled the scene, but later turned himself in. He and a passenger in the car told police that they had been "intentionally inhaling chemical vapors," or "huffing," just before the crash.

Judge James Isaacson, who handed down the sentence, told Treu it was "hard to label" what he did.

"You know it's been called a tragedy — that doesn't seem to be enough. It's been called a horrendous tragedy; senseless, thoughtless," Isaacson said. "There's more adjectives. Avoidable is one that comes to mind. Still it's not enough."

In closing arguments, Treu's defense attorney, Carly Sebion, asked that the court "remember that Colten Treu isn't the sum of just those bad mistakes on that one day."

During sentencing, the defense team also repeatedly brought up the passenger who was in Treu's car during the crash. That man, John Stender, has not been charged, but Chippewa County District Attorney Wade Newell said he is expected to be charged by the end of the week with intentional abuse of a hazardous substance and aiding a felon.

Newell said after sentencing that he would have preferred a longer sentence for Treu, "but I think justice was served though and that he was held accountable for what he did on Nov. 3, 2018."

The Girl Scouts of the Northwestern Great Lakes said in a statement that the organization was "thankful for the sentence handed down today for the deaths and injuries of our beloved Girl Scouts."

"We remain fully in support of Troop 3055, their families, and our Girl Scout community and hope today’s sentencing provides some small measure of closure as the families continue to try and rebuild after immeasurable loss," the statement said.

CORRECTION (March 13, 2020, 1:48 p.m. ET) An earlier version of this article misstated the age of Colten Treu, who was sentenced for a crash that killed three Girl Scouts and a mother. He is 23 years old, not 22.