A western Wisconsin pickup truck driver was drunk when he hit and killed three Girl Scouts and a parent picking up litter over the weekend along a western Wisconsin highway, authorities said Monday.

Colton Treu, 21, of Chippewa Falls, was expected to appear in court late Monday morning on 13 possible charges, including four counts of homicide by intoxicated use of a vehicle, according to Chippewa County Sheriffs Sgt. Robert Jensen.

Also Monday, authorities were prepared to release the identities of those killed in the crash late Saturday morning along County Road P near the Hwy. 29 overpass in Lake Hallie.

Treu was speeding in his pickup when it veered off the road and into a shallow ditch where some of the fourth-graders and the mother were collecting litter as part of a larger Adopt-A-Highway group walking along both sides of the road, according to police and witnesses.

Two girls and the mother were dead at the scene. Two other girls were taken by ground and air ambulances to a hospital, where one of them died later Saturday. The other girl was initially reported to be in critical condition.

The girls were students at the Halmstad and Southview elementary schools in the Chippewa Falls School District and members of Troop 3055. Counselors were being made available to students and staff when classes resumed Monday.

In front of Halmstad Elementary, teddy bears, balloons, candles and a bouquet of flowers sat on two wooden benches Sunday afternoon. Inside, dozens of families met with faith leaders and counselors, as they did at Southview.

Hundreds of people gathered Sunday night in the rain outside Halmstad to remember the Girl Scouts and the mother who were struck while making their community a better place to live.

It was heartbreaking, Tabatha Kolve, 18, a Girl Scout and a troop leader who helped her fourth-graders assemble 150 candles for the vigil. She drove in from Eleva-Strum, 30 minutes away. There isnt much to say because it was so upsetting.