The remains of three young children were discovered in Tennessee after someone stumbled across a human skull in a heavily wooded area of Memphis last month, according to authorities.

An investigation began on March 8 after an anonymous caller reported finding a human skull near a wooded area in Hickory Hill, located in southwest Memphis, Memphis Police Chief Cerelyn Davis said at a press conference on Wednesday.

Officers located the skull near the edge of the woods and brought in cadaver dogs to extensively search the area over the following days. The dogs alerted officials to a drainage pipe — suggesting more human remains could be there.

On April 1, investigators located an additional human skull after assessing the drainage system. The next day, search teams canvassing the area found 14 additional bones “consistent with human remains,” Davis added.

Initial analysis done by a medical examiner confirmed that the remains belonged to three children between the ages of 3 and 7, police announced.

“Our goal today is to conduct a thorough and methodical search of the area for additional evidence that will assist in identifying the deceased,” Davis said at the press conference.

Investigators are still determining the children’s identities and the cause of death.

“We understand that this information is very difficult and deeply concerning to all of us. We want to reassure the public that there is no indication of any active threat at this time,” she added.

“Somebody knows where these children have come from. Someone knows the missing children that we have discovered in this area. It’s heartbreaking. It’s disturbing.”

Roughly 170 personnel are involved in the search of the crime scene, including federal agencies such as the FBI, she said.

An investigation remains ongoing, and anyone with information is urged to contact the police.