Police say members of a radical Islamic sect likely killed a high-ranking police officer and a child in northeast Nigeria.

Borno state Assistant Police Commissioner Usman Baba said Thursday that the police superintendent assigned to guard the state government headquarters died in the morning attack, as well as a child opening a garage door.

Baba said the three gunmen likely belonged to a radical sect known locally as Boko Haram, which is blamed for a series of targeted assassinations.

Meanwhile, in neighboring Gombe state, three boys died in an explosion Thursday apparently caused by a bomb left over from a bank robbery the day before. Police say the boys picked up the explosive while playing in a garbage dump without knowing what it was.