Police say Amierah Roberson's mother was at work, and the girl was being watched by another adult. That person said they turned their attention from Amierah for a minute and she was gone.
Anyone with information is asked to call chicago police.
Amierah lives with her mother and grandmother in Calumet City. Neither woman was caring for the 19-month-old when she disappeared.
"My daughter called me frantic yesterday evening about 5:40, saying when she went to pick Amierah up they were supposed to be waiting for her downstairs because the building is a high-rise building. She pulled up to get Amierah and then she was informed that Amierah was missing," said Bernadette Madison, Amierah's grandmother.
Amierah is tall for her age - often mistaken for being older than she is. That's one reason Madison fears the toddler found dead Sunday in Riverdale could be the little girl who affectionately calls her "Ma."
"It's a little ironic that on the day she went missing another child was found dead," Madison said.
Madison wouldn't name the person who was caring for Amierah while the toddler's mother was at work because the investigation is ongoing.