The officers were doing a wellness check last month in the Englewood neighborhood when they found the three children -- ages 1, 2 and 7 -- now known as the "Englewood angels."
The girls had been left alone in an abandoned house.
"When I arrived they were all huddled up in a bedroom on a very dirty mattress that was inside one of the bedrooms there," Sgt. Charles Artz said. "The whole house was very uninhabitable. There was no running water, no heat, no electricity. Dirty garbage was spread throughout the apartment. Feces was evident, dead rodents were evident inside the house ... just a very sad, sad situation for three little girls to be in."
It's unclear how long the children had been in the abandoned home.
The father was accused of striking his children, and charged with eight counts of battery. He has pleaded not guilty. The mother's role in the children's lives is unclear. After getting checked at a hospital, the girls were placed in the care of their paternal grandmother, Delores Anderson.
When Anderson first saw how dirty and malnourished they were, she said she felt hurt and disappointed.
"I'm just glad they are with me now because they had no heat and running water and no one should have to live like that," she said.
But Anderson wasn't in a position to provide for them financially, and she had to quit her jobs to take care of the children. Officer Mimi Bugarin and others joined Artz and immediately wanted to help.
"I have two daughters myself. It was heartbreaking to see them in the conditions that they were living in. We just knew that we needed to do something more for them," said Bugarin.
They started by dropping off diapers and milk to the girls' grandmother when they were off duty. While off duty, they also started a GoFundMe account that has collected more than $125,000
, and they've collected a room full of gifts at the District 7 police station.
People from all over the country and around the world have made donations.
In the six weeks or so since the girls were rescued, they have gained more than seven pounds each and experienced some of the joys most people take for granted.
Officer Janice Wilson was especially moved by the fact that the eldest child had never heard of Santa Claus.
"She had no idea what it was like to be in the presence of Santa Claus and what the purpose of Santa Claus was," Wilson said. "She had never experienced the parts of Christmas. An officer, out of his own pocket, went and bought a tree to donate to the family and they got a chance to experience decorating it. You know, trimming the tree for the first time."
The eldest child also had never been to school. But thanks to the officers of District 7, not only is she in school now, but they've also arranged for her to receive one-on-one instruction to help her catch up with the rest of her classmates.
Their grandmother, who raised five children of her own, has found sometimes there is a light at the bleakest of times.
"Of all the things that I have lived through all my life, I never thought there were still so many people in this world that care," she said. "And everything that you see going on in Chicago today, anywhere really, but mostly in Chicago, it just seems like there's no caring, there's no respect, there's no love anymore, and for everybody to reach out, to donate what they can ... food, money, clothing for the girls ... and they try to help me, too, but I don't want anything. As long as my babies OK and I got a roof over my head, I'm fine."