Updated

Two people died Thursday in what a coroner called "inter-related" cases involving a fatal house fire near St. Louis, followed shortly by a baby found alive inside a car in a lake.

The chain of events began around 5:30 a.m. when children ran to a Wal-Mart store in Glen Carbon, Ill., and called 911 to report their house was on fire. Authorities said an adult died in the fire but six children, siblings ranging from very young to teenagers, escaped. Property records showed the home belonged to Cristy Lynn Campbell.

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Around 6 a.m., a car was found submerged in Silver Lake in Highland, Illinois, about 16 miles from where the house burned. An infant was found alone in the car. Rescuers administered CPR and the child was taken to an undisclosed St. Louis hospital. The child's condition was not immediately available.

A body was found in the lake shortly before noon. Authorities have not disclosed any details.

Madison County, Illinois, Coroner Steve Nonn said in a news release that his agency was investigating "two inter-related" incidents that involved "the deaths of two Madison County residents." Nonn did not elaborate and did not return phone messages seeking comment.

Highland Fire Capt. Brad Menz said the car appeared to have rolled down a hillside into the lake near Illinois Route 143.

Soon after the car was found, Glen Carbon police issued an advisory describing Campbell as a "person of interest" and "possibly endangered."

Campbell has seven children, authorities said. Six escaped the house fire and Glen Carbon Fire Chief Ralph Well told the St. Louis Post-Dispatch that authorities suspect the infant found in the lake is the seventh.

Court records show Campbell, 32, married Justin Campbell on Nov. 3, 2006. She filed for legal separation in September 2010, but the matter was dismissed two months later.

In April 2012, Cristy Campbell obtained an emergency protection order against her husband and filed for divorce, alleging in court papers that he "abuses me on a weekly basis," including punching and choking her.

"He has told me that I'm a no good wife," Campbell wrote in her application for the protection order.

The divorce was granted in February 2013.