Chicago police say they found a toddler’s head, hands and feet this weekend near a lagoon in the city’s Garfield Park, the Chicago Tribune reports.

According to Alderman Jason Ervin, the victim is believed to have been between one and four years old.

Authorities say the limbs were unclothed and in advanced state of decomposition. CNN reports it is currently not known if they were from the same body. From WMAQ-TV:

Police have also begun looking through missing children reports in the city and state and have contacted the National Center for Missing and Exploited Children, [Chicago Police spokesperson Anthony ] Guglielmi said.

Detectives have not yet determined the identity of the remains or the cause of death. The evidence will be sent to the Cook County medical examiner, who will be able to determine the manner of death in the coming days, according to Guglielmi.

“Cases involving children are exceptionally difficult for all affected—even police,” Guglielmi told WMAQ-TV. “We will comb every square inch of the lagoon for whatever may or may not be in there.”

“We are not talking of a newborn, and we are not talking about a first grader,” Ervin said at a press conference on Monday. “This is someone who should have been noticed is not around.”

[Image via WLS-TV]