A search warrant said a man accused of running down his young son and the boy's mother confronted her about a new relationship just before striking them with his SUV in Fitchburg.
The boy was still pinned underneath one of the vehicle's wheels when police arrived at the scene Monday. Two-year-old Yandel Castillo-Castillo was killed. His mother, Maria del Rosario Castillo-Castillo, was injured.
The mother and child were returning home from lunch with Miguel Menendez-Ruvalcaba when they were confronted by the child's father, Jesus A. Castillo-Dimas, 30.
The warrant said the father told the child's mother "you'll see what's going to happen to you and your child," then accelerated and struck them, according to a Wisconsin State Journal report.
Police said Castillo-Dimas then got a knife from his SUV and stabbed the mother. She survived puncture wounds to her neck.
Fitchburg police said the case against Castillo-Dimas has been turned over to the Dane County District Attorney's Office.
Castillo-Dimas remains jailed on suspicion of first-degree intentional homicide and attempted first-degree homicide.
Police said they are looking at any potential history of domestic incidents.
"We'll be looking at things like what's the history between the two of them, when specifically did the relationship end? What's been the behavior since the relationship ended? Those sorts of things as we try and piece together what I'd call the back story," said Lt. Chad Brecklin of the Fitchburg Police Department.
Fitchburg police said they are urging residents to contact authorities if a domestic abuse scenario appears imminent.