Police have charged the cousin of a 16-year-old girl who was stabbed and killed Tuesday with murder.

Police say 15-year-old Tiana Brown killed Shannon Braithwaite inside of an Empire Boulevard apartment. Braithwaite's mother says Brown is a chronic runaway and the family had just recently taken her in Sunday.

According to police, Braithwaite was found by her mother Tuesday inside of their apartment on Empire Boulevard. Police say she was laying in a pool of her own blood.

Braithwaite's aunt tells News 12 Brooklyn that the teen recently finished a summer job at the Brooklyn Children's Museum and always stayed out of trouble.

Police also reportedly found a bloody knife inside the apartment.