...but the dispatch officer told him to put the gun down and wait for police.
Perfect example as to why one must be prepared to defend oneself, they very well could have just sent a hearse buy the time the police showed up.
I suspect you're just kidding, but it's worth mentioning that no homeowner in such a situation should consider tampering with evidence.
It destroys all of the homeowner's credibility. And I doubt very much that it would fool an experienced detective.
That is extraordinarily wrong and stupid advice. You will always get caught and it will not look good if you go to court. Even if you manage to clear yourself of the homicide charge, you'll be done on obstruction of justice.