MARKHAM, Ill. – Investigators discovered a gun in a burning, abandoned home in Markham, where a baby girl was found dead Monday morning, a source revealed to WGN News.

The South Suburban Major Crimes Task Force, which is searching the home for clues, is now also investigating the case, WGN confirmed.

Authorities said that the baby girl was believed to be about 12 months old. She has not yet been identified.

The baby was found inside a plastic bag on the upstairs floor of the home, which is possibly an attic, at the 155th and Hamlin.

An autopsy is scheduled to be conducted today to determine the child’s cause of death.

Police were alerted that something was wrong at the location early Monday morning after a neighbor called 911 to report the house was burning.

It was around 6:30 a.m. and plumes of smoke were visible from the roof of the home.

Once crews got inside and discovered the baby, Markham called in the state police crime lab.