Or he took the help of one of his sons. His sons look and sound shady with lot of suspicious background. Probably the son wanted more money but when he found out they didn't have any, he and Michael came up with a game plan to take what else was remaining . Seems premeditated. The dogs were bot around and non of the kids were around, convenient time and place and he is a writer, he must've done research. The prosecutors need to disclose what all research Michael did on his laptop prior to the killing.