An autopsy was inconclusive for a suburban Chicago man who authorities say killed his wife and two children.

The Southtown Star reports authorities are waiting for toxicology results for 43-year-old Michael Worsham.

His body was found inside his Robbins home along with the bodies of his 17-year-old son, 15-year-old daughter and wife. Investigators say he shot all three on Sunday. A 14-year-old stepson escaped with the boy's 5-year-old nephew.

Police say Worsham didn't have gunshot wounds.

Investigators in the Cook County Sheriff's Office say they're not sure what prompted the slayings. But they're calling the shootings a "tragic mystery."

Meanwhile, mourners are leaving crosses, candles, teddy bears, flowers, balloons and other items near the home that's just south of Chicago.

Risto Viitanen