A preliminary autopsy report says a kindergartner who collapsed on a playground during a West Michigan elementary school's field day had a small rock or stone blocking his airway.
The Muskegon Chronicle reports authorities on Thursday issued an update on the investigation into the death of 6-year-old Nikolas Wypa.
Police were trying to determine how and why he ingested the rock, but they say foul play isn't suspected. He was reportedly playing with sidewalk chalk at the time.
Nikolas was unresponsive Monday afternoon at Churchill Elementary School in Norton Shores before being taken to a hospital, where he was pronounced dead.
Officials have said his mother was volunteering for field day and was quickly at her son's side.