An autopsy found that Schranz had been stabbed to death.
Investigators still have not determined how long Schranz had been dead, and they are now searching for other clues in the case.
Schranz was reported missing by her mother in October.
"She tried so hard to get her life cleaned up," said mom Rebecca Stowers. "The drugs were stronger than she was."
Stowers' decades-long nightmare had its worst possible ending last Friday when the body of her drug-addicted daughter was found frozen, stabbed and dismembered in a snow-covered field on the city's Southwest Side.
"Nobody should die like that," Stowers said. "I don't care what her lifestyle was."
Schranz had five children ranging in age from 19 to 6 years old; she lost custody of all of them.
Friends say she worked as a prostitute along Archer Avenue in southwest suburban Summit. Deena Patterson said she saw and talked to Schranz on Archer last October, the night before she disappeared.
"She said if something ever happens to her, her boyfriend did it," said Patterson. "She told a lot of people that."
Stowers says she filed a missing persons report last October, circulated hand-made fliers and tried unsuccessfully to get news media help in the search for Schranz.
Summit police would not comment on the now-missing boyfriend or any facts in the case, which is now being investigated by Chicago police.
Stowers demands that investigators give the case priority, despite her daughter's habits and what she did for a living.
"I don't want her life to mean nothing," she said.
Chicago police will not say anything about the case except that it's under investigation. But the victim's mother says she was told by investigators that her daughter was killed at another location and the body moved to the Southwest Side field where it was found.