That was one of the "first" reports. It was incorrect. Most accounts (including post-mortem examination) indicate the rifle was used in the killings.
Of course, ALL details on the investigation are now on close hold and/or buried, so who knows what really went on? The truth could be anything.
I’m sorry,but I must dispute you.NBC reported(early on)that an”Assault-Rifle”had been found in the perp’s trunk.Then they”hushed it up”!