CHICAGO (AP) — Chicago police say a man fatally shot his son and daughter, both 10 years old, and then turned the gun on himself in their North Side apartment.

Police say they were called to the residence Monday morning after a nanny was unable to enter the apartment. There they found a 45-year-old man dead from an apparent self-inflicted gunshot wound. The children, twins, were found elsewhere, both with gunshot wounds to the back of the head.

The Cook County Medical Examiner identified the children as Mason and Addison Sanders. The father's identity has not been released, pending notification of next of kin.

Police say they didn't have any prior contact with the father. Authorities did not reveal a motive for the double murder-suicide.