Indiana State Police said the Lake County Coroner has positively identified the remains as that of Jaclyn "Angel" Dobbs, who was reported missing after her mother was found murdered earlier this week.
Construction workers called 911 after they spotted a body floating in a retention pond off I-80 near Kennedy Avenue in Hammond just before 12 p.m.
Indiana State Police said investigators were able to quickly find the body of a Black, female child. They said the pond was relatively full of water from recent rain - about 4 or 5 feet deep - and easily accessible from the nearby roadway.
After identifying the body, the Lake County Coroner is expected to conduct an autopsy Friday morning to determine how she died.
The search for Dobbs stretched from Illinois to Missouri, then Indiana. Dobbs was reported missing after her mother was found dead in her Wheeling apartment Tuesday night.
Police making a well-being check at an apartment building in the 300-block of Inland Drive Tuesday night found a woman dead and her 1-year-old daughter missing.
Ja'nya Murphy, 21, was discovered unresponsive about 10:20 pm. Tuesday after officers climbed onto a balcony and entered her apartment, according to Deputy Police Chief Al Steffen.
Murphy appeared to have been murdered, and her daughter, whom they called "Angel," was not in the home, Steffen said.
The Cook County Medical Examiner's office said Thursday that Murphy died as a result of strangulation. Her death has been ruled a homicide.
Steffen said it appeared Murphy had been assaulted, and they are eager to find her daughter. Angel is believed to be in danger, police said.
"We need the public's assistance with this," Steffen said. "They might be able to connect the dots, connect a link that we don't have right now."
Wheeling and Illinois State Police activated an endangered missing person advisory early Thursday morning after a car the girl was believed to be in turned up in Missouri Wednesday without her in it.
Authorities believed the child was in a rented 2020 Maroon Dodge Caravan with Illinois plates.
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Investigators also identified a person of interest connected to the Dodge Caravan, who had a previous relationship with Murphy and was seen with her on video Monday.
That individual was also found in Missouri, police said.
"We know for a fact he was in the far northern suburbs yesterday morning and then by yesterday evening, he was in western Missouri," Steffen said. "We are looking to recreate the track from where he was in the northwest suburbs to Missouri."
Murphy was a 2018 graduate of Stevenson High School and lived with her daughter at the apartment building, Wheeling police said.
Murphy's high school best friend said he was shocked when he read about what happened.
"It was mind blowing to me to read the first article; I didn't want to believe it. I still can't believe it," Brentley Wright said. "There is no way, there is no way this is possible; there is no way this is happening. It's crazy to think, one, that it happens so close, and, two, someone I was like best friends with in high school."
The Major Case Assistance Team was called in to help collect and process evidence.
Police went to the building after Murphy had not been to work Tuesday and had not been seen by relatives since Monday, Steffen said. With help from the fire department, officers climbed onto Murphy's balcony, finding the door unlocked and discovering her body inside.
Steffen said Murphy would drop Angel off at relatives' before work, but she didn't drop off the baby on Tuesday, and she didn't show up at her retail job. Murphy's family last talked with her Monday.
Anyone with information should call Wheeling police at (847) 459-2632 or 911.
The Sun-Times Media Wire contributed to this report.