Boston Police are investigating after a 3-year-old child died Tuesday night.

Police officers late at night responded to a radio call for a 3-year-old child in cardiac arrest at 9 Hannon St., in Mattapan.

Upon arrival, the cops learned that the child had been transported to a local hospital for evaluation and treatment.

Officers then went to the hospital, where the child was pronounced dead.

“Homicide Detectives responded to 9 Hannon Street, which remains an active crime scene as the investigation continues,” a Boston Police spokesperson said in a statement.

“At this time, no arrests have been made,” the spokesperson added. “The incident remains under active investigation, and additional details will be provided as they become available.”