Strange they would have the Van locked up and alarm set parked in the garage in the nice neighborhood they lived in.
Could Susan have ran to the Van to get out knowing the keys were usually left in it since it was in the garage and Josh had gotten the keys earlier and locked the van and set the alarm?
I see nothing strange in locking your vehicle when you are not in it, no matter where it is parked, but I lived most of my life in London where car theft is rife.
Our car automatically locks all the doors except the driver's door when you exit the vehicle, which i personally find very annoying as I often leave things on the back seat and want to get them out, but my wife likes for the extra security.
Does anybody know if there was just one set of keys to the van, and if Josh kept them? His history of controlling behaviour would suggest he kept the keys, but it's also possible there were several sets.
Two minutes seems a long time for an alarm to go off when the owners are clearly within hearing range, but I couldn't count the number of times I've been woken in the small hours by car alarms going off, and the owner is far slower to shut it off than I would be.
It ought to be common practise for neighbours to investigate car alarms, but you never know if you'll get involved in a situation yourself. In a country where almost anybody can own a gun and you might not know about it, I can understand the reluctance to get involved.
The 2-minute alarm (continuous, not interrupted?) does suggest a possible scenario to me. Susan goes for the van saying she is leaving Josh, Josh tries to stop her, fight ensues and alarm is set off, Josh wounds her mortally and tries to drag her back into the house (possibly with the idea of calling for help) but she dies, and he leaves her lying on the living room carpet where she bleeds out. He panics for a while, then decides on trying to clean up and dumping the body because he can't face the music.
Whether Josh killed Susan in the living room, in the garage or elsewhere, I'm still of the opinion that it wasn't premeditated because even he would have a better alibi. He must know that his ludicrous self-contradicting story is focussing suspicion on him, cand he can't talk to anyone about Susan without admitting the story is utter bollox.
He's got himself into a situation and now he's desperately hoping his crime is not discovered, because he can't face the consequences. LE are gathering the evidence, and he's sh*tting bricks.