Angry client kills 2 Chicago IP lawyers

I thought last year's patent lawyer murder-suicide was a rarity. This year, not only did we have the "vigilante" patent lawyer allegedly killing his neighbor, but today this week we also hear of a Chicago patent lawyer's client killing two attorneys and another firm employee before being fatally shot himself by police.

[the client] told witnesses before he was shot that he had been cheated over a toilet he had invented for use in trucks

Is it just a coincidence there were patent attorneys involved in these cases? Granted, today's event is different because it's the client who apparently "snapped," but you still wouldn't expect to hear that happen over a patent case.

It will be interesting to find out how much $ was at stake and whether the attorney(s) involved had any indication the client was capable of something like this.