St. Clair, MO- Carbon monoxide poisoning is suspected after the bodies of two adults and two children were found in a home in the eastern Missouri town of St. Clair.

The St. Louis Post-Dispatch reports that investigators do not suspect foul play in the deaths of 29-year-old Angela Sohn, her 27-year-old boyfriend, Ryan Yoder, and his two children, 4-year-old Devin Yoder and 3-year-old Tessa Yoder.

The bodies were found Thursday afternoon after friends went to check on the family. St. Clair Police Chief Bill Hammack says it is unclear when they died.

Three bodies were found in a bedroom, and the fourth on a couch.

Relatives told police that Sohn and Ryan Yoder had complained early in the week of being sick with nausea. They were last seen alive Tuesday.

Autopsies are planned.