Cahokia School District 187 officials notified parents Wednesday of three suspicious instances involving students in the past week.
Superintendent Art Ryan said the parent of a kindergarten student reported on Tuesday that a man came to their home asking for the child by name and if the child was ready to go to school.
On Wednesday morning, a fourth grade student walking to school was approached by a man. And, last week, a second grade student reported that a man followed her to school.
The district made automated phone calls to parents after learning of the three cases that involved similar suspect descriptions, Ryan said.
The man is described as a white man between 40 and 50 years old, about 6 feet tall and 180 pounds. He drove a silver Lincoln or similar vehicle.
Police are investigating and anyone with information is asked to call the Cahokia Police Department at 337-9500.