A 20-year-old mother faces murder and manslaughter charges in connection with the death of her 19-month-old son, who was found unconscious in their Brooklyn apartment Sunday evening, police say.

Officers responding to a call about a disturbed woman at a home on Ocean Avenue in Flatbush around 8 p.m. found little Justin Stephens unresponsive, according to the NYPD.

He was pronounced dead at the hospital.

Anna Thomas, Justin's mother, was taken into custody at the scene and questioned by police for several hours. She was later arrested.

Information on an attorney for Thomas wasn't immediately available.