That is one possibility. But knocking us off 3 or 10 at a time doesn't seem too economical. Not enough bang for the buck. Maybe it's another guy who lost his job or is losing his house. Could be something more sinister too tho.....
In a society where you strap bombs to your children, and kill any wives who piss you off, I don't think economy is their first concern.
If it starts happening on a regular basis, it will create the “terror” they always desire... I haven’t read a lot about this particular case yet, just wanted to mention that.