The suspect, a resident of Torsillo Street, Dagat-Dagatan, Caloocan, is now detained at the Department of Social Welfare and Development.
Police reports showed that the girl was sexually abused by the suspect after midnight last Tuesday.
The victims mother told authorities that her daughter left their house before midnight to go to a nearby public restroom.
But when the victim failed to return home after 30 minutes, her mother ordered her other daughter to see why the victim was taking so long.
The other daughter was shocked to see the suspect in the act of raping her sister and immediately told her mother.
Both sought help from barangay officials who arrested the boy. Matthew Estabillo