http://www.youtube.com/watch?v=ZDmbi4hYEtY
It would be interesting to locate the Lanza's car in other video/images to determine if the trunk was open. If the trunk wasn't left open by Lanza, I'd call BS on reports of it being located and the trunk opened within 20 mins of dispatch. In the video above, the taping of the shotgun being removed occured after dark and the reporter mentions the gun was found in just the last 30 mins.
one of the news reports said the shotgun was capable of firing up to 20 rounds...
I am assuming that the handgun[s] that he killed himself with would have been near his body while the rifle may have been tossed away and thus found by itself some distance from his body -- perhaps even in a different room. Thus they would quickly associate the handguns with him but not the rifle initially. They might have thought that since it was found by itself that it had been used by a second shooter and not by Lanza.
Agreed. No way would any known gun be left laying around all day and not secured in evidence immediately. We see video of his car with nothing but crime scene tape guarding it.