KANDAHAR—An investigation by Canadian military officials has confirmed that insurgents in Afghanistan were responsible for forcing down a Chinook helicopter in August.

But the investigation failed to determine what weapon the Taliban used to bring down the the big aircraft.

The Chinook was carrying 21 people when it was forced to make a so-called “hard landing” in the Panjwaii district, southwest of Kandahar city.

Eight of those on board suffered minor injuries.

The military initially indicated the helicopter suffered small-arms fire.

However, Air Wing Commander Col. Paul Prevost says the Chinook appeared to suffer too much damage for that to be the case.