CHICAGO (CBS) — Chicago police have released a sketch of the toddler whose severed head, hands, and feet were found in the Garfield Park lagoon over the weekend.

“I’ve got to tell you that this is gruesome work,” Police Supt. Garry McCarthy said as crews continued draining the lagoon on Thursday, and using cadaver dogs to search for the child’s torso, which has not yet been found.

So far, police have been unable to determine the gender, race, or exact age of the child. The Cook County Medical Examiner’s office has said the body parts are from an African American or mixed race child between the ages of 2 and 3 years. The child most likely had short, curly black hair, brown eyes and the earlobes, suggesting the child might be a boy, but it can’t be ruled out that the child was a girl.

Police enlisted the help of a Cook County sketch artist to create a composite drawing of what the child might have looked like, hoping someone might recognize the toddler and help investigators identify him or her. McCarthy said somebody knows something about the dead child.

“As a parent, I’m troubled, really troubled by this, as we all are. One of the things that we’re making sure is that our officers are okay. Recovering body parts is not an easy thing to do. It’s a gruesome task, but it’s something that needs to be done,” he said.

The superintendent said police would not rest until they solve what he called a “heinous, senseless event.”

“We’ve done a lot of really good strong work, but we’re going to need help from the public. People should be outraged. Whether or not this is a murder, we don’t know at this point,” he said.

Police have received about 150 tips, according to Chief of Detectives John Escalante.

“We want anyone that has any information, anything they think is suspicious or unusual, to continue to call,” he said.

Escalante has said investigators believe the body was in the lagoon for one or two weeks, but not much longer.

Crews have been pumping water out of the lagoon and into local sewers, in hopes of finding the rest of the child’s dismembered body, and any other evidence that might help them figure out how and when it was dumped in the water.

The child’s foot was found in the lagoon Saturday afternoon. Police later found the child’s other foot, both hands, and a 20-pound weight nearby. On Sunday, the child’s severed head was found.

Several plastic bags were found in the lagoon, but police have not said whether the bags had been used to dump the child’s body parts.

DNA samples have been submitted and a dental consultation has taken place, according to a joint statement from the medical examiner and Chicago police. Fingerprints and footprints have been taken by police. Chicago police also have begun working with a Cook County sketch artist to create a composite drawing to determine what the child might have looked like.