But the Associated Press is quoting a law enforcement source who says a gun found in the car of the two suspects is a ballistic match to the 223-calibre rifle used in the attacks.
A source says the weapon found in the Chevrolet Caprice was a Bushmaster.
An executive with Bushmaster says the company got an inquiry from the ATF today about a specific AR-15 sold to a distributor in Washington state in June.
The AR-15 is the civilian form of the M-16 military assault rifle -- it's a semiautomatic rifle that costs about $900 US.
They're sold through distributors only, not direct to consumers.