CHICAGO (CBS) — Chicago Police detectives seek someone for questioning in the death of the two-year-old Rockford boy whose body parts were found in the Garfield Park Lagoon on the city’s West Side.

A Chicago Police Department media spokesman refused to identify their “person of interest,” how the person fits into the case or if the person knows victim Kyrian Knox or his mother, Lanisha.

Detectives revealed last week that the severely-decomposed foot, hands and head found in the lagoon Sept. 5 were those of Kyrian, based on DNA taken from his mother, who has told Chicago and Rockford police that she left the boy with trusted family friends while starting a new job. She has claimed that she asked repeatedly to get the boy back only to be given a series of excuses.

Kyrian was last seen alive in mid-August. Rockford Police first contacted Chicago Police regarding the case in mid-September, after the body parts were discovered.

To date, the boy’s legs and torso have not been found. The Cook County Medical Examiner’s office has not been able to determine the cause or manner of death.

“Anyone that can do something like that to a two-year old baby is just not a good person,” said Cameshia Harris, the victim’s grandmother. “They are not even fit to walk the earth with us regular people.”

Harris says the news that police have identified a person of interest giver her hope they’re close to an arrest.

“We’ve known all the time who the suspects were, this just lets me know that they’re working,” she said.