Boston Police Commissioner Ed Davis said investigators believe the terrorist Tsarnaev brothers were planning more attacks to kill Americans based on the amount of firearms and explosives recovered at the scene of Friday’s shootout with police.

Davis described the incredible amount of homemade explosives and other weapons the Boston Marathon bombing suspects used during the confrontation with police that killed Tamerlan Tsarnaev Friday in Watertown.

We have reason to believe, based upon the evidence that was found at that scene — the explosions, the explosive ordnance that was unexploded and the firepower that they had — that they were going to attack other individuals,” Davis said Sunday on “Face the Nation.”

“This was as dangerous as it gets in urban policing,” Davis said.

Watch Davis on CBS’s “Face the Nation” Sunday: