I think MH said they dropped the dog at the grandmother's house while they made the drop, then went back for the dog. Not sure who ended up with it.
He said he didn't mention the toolbox to LE because he didn't think it was relevant. If he thought there were drugs in it, it wouldn't have been. Had he known the gun was in it, who knows whether he would have mentioned it.
It didn't state that AM failed to mention the backpack, so I'm assuming that he *did* mention the backpack even though it had drugs in it?