The other possibility is that the theft was contracted by someone who simply wants to have it. They'd have to keep it secret of course, for a very long time. This would be a wealthy individual, perhaps someone who has tried to buy it in the past only to find it not for sale.
I only just now read the WHOLE article,from JS online, and think you’re right.I didn’t know a stun gun was used,or any of those other details.Yes, it looks like someone just Wanted it. I expect a sting operation will be assembled soon.