He will be charged with four counts of homicide, Lake Hallie police Sgt. Daniel Sokup said.
Ms Schneider said the deaths of her daughter and granddaughter were "still not real for any of us". The injured 10-year-old girl was in stable condition on November 5, police said.
This is the six month-old baby boy who was killed after a 10 year-old girl allegedly stomped on his head.
The station also spoke with Pastor Jim Woldhuis, who presides over the Chippewa Valley Bible Church where Hickle and her mother attended.
According to Fox News, Treu's vehicle veered into the ditch where the volunteers were picking up trash, and he drove off after hitting the victims. Both subjects gave statements to police which included that they had been intentionally inhaling chemical vapors which is commonly called "Huffing", just prior to the accident.
Police questioned one adult and three children who were present at the day care center. The mother of one of the girls killed said she was standing near her daughter when the truck came crashing toward them. Ten-year-old Haylee Hickle and her 32-year-old mother, Sara Jo Schneider, from the Town of Lafayette, were also killed. The baby was found to be unresponsive and bleeding from the head, according to officials. He is jailed on 13 possible charges, including homicide by intoxicated use of a vehicle. Authorities said Treu sped off after the collision, but surrendered hours later.
Jensen says Treu will have a bond hearing at 10 a.m. Monday.
CNN has been unable to reach Treu, who does not yet have an attorney.
There's now a makeshift memorial outside of the victims' elementary school in Chippewa Falls. The City of Chippewa Falls Police discovered the truck abandoned in the garage at the home, but neither the driver nor the passenger was still at the location, police said.
The girls were fourth-graders and members of Troop 3055 in nearby Chippewa Falls, about 90 miles (145 kilometers) east of Minneapolis.