All members of the group - seven children and five adults - "were in the ditch, not on the pavement or gravel shoulder at the time of the crash" and were "wearing green highly visible safety vests", police said.
"She stated she was holding the child and that's when she dropped the child", Wade said.
The 11 charges filed against Colten Treu on Tuesday include four counts of vehicular homicide and four counts of a hit-and-run resulting in death.
Authorities say a 21-year-old driver was intoxicated when he struck and killed three Girl Scouts and a parent and critically injured a fourth girl along a rural Wisconsin road.
Eliopoulos said the school day on Monday started with counselors, faith based leaders, teachers and trusted adults on school campuses offering support services.More news: Barty beats Wang to win WTA Elite Trophy final
Lake Hallie Police Department Chief Cal Smokowicz did not specify in his release what chemicals Treu admitted to inhaling before the crash.
Colten Treu, 21, drove his pickup truck into the group of Scouts, the Lake Hallie Police Department said.
Schneider's daughter, 32-year-old Sara Jo Schneider, and granddaughter, 10-year-old Haylee Hickle, were killed along with 9-year-old Jayna Kelley and 10-year-old Autum Helgeson, both of Lake Hallie.
He appeared in court via video Monday and was held on $250,000 cash bond.More news: Mac Miller Died of Fentanyl, Cocaine Overdose
The girls were students at the Halmstad and Southview elementary schools in the Chippewa Falls School District and members of Troop 3055.
Meanwhile, a GoFundMe account has been established for the families of those who lost their lives during the Girl Scout trash cleanup. A makeshift memorial of teddy bears, balloons and candles was set up on two wooden benches.
"Our hearts are broken for the girls and families of the Girl Scouts of the Northwestern Great Lakes", Sylvia Acevedo of Girl Scouts of the US said in a statement. "The Girl Scout Movement everywhere stands with our sister Girl Scouts in Wisconsin to grieve and comfort one another in the wake of this bad tragedy".
District superintendent Heidi Eliopoulos issued a message to parents saying, "This is a hard time for our students, families and staff".More news: Spice Girls 2019 live tour announcement as band gets back together