The body of a baby boy was recovered from Lake Michigan last night in the South Shore neighborhood.
He was allegedly drowned by his mother.
A woman was in the lake screaming, according to witnesses, near the South Shore Cultural Center.
It was 9:45 p.m.
Another woman who was a witness recorded video that was posted on social media.
She said she thought the woman was drowning.
She was screaming and going out far from shore.
When she came in closer, the witness said, the woman screamed "I killed my baby and I wanna die with my baby."
Police found the 31-year-old woman in the water.
They arrested her and then searched for the baby.
Boats from the police Marine Unit were in the water.
A helicopter was overhead.
Witnesses reacted with horror when the Marine Unit recovered the baby's body.
The video showed a baby bag on the beach.
There were photos of a baby boy inside.
The 31-year-old woman was taken to the University of Chicago Medical Center for an evaluation.
The body of the 1-year-old boy was taken to Comer Children's Hosptial where he was pronounced dead.
Police say this is a homicide investigation.