My office is usually open. After all, our customers have to get in. But from today it'll be locked up like Fort Knox: a colleague got a murder threat from a former employee today and the police takes the threat serious.
It's pretty hard to believe - I've known that guy for years and he was always very friendly. Everyone thinks he must have some sort of mental illness or perhaps a brain tumor or somesuch. It's pretty horrible to have to be afraid of someone you have known and trusted for so long. It reminds me a bit of my granny who during a stroke suffered such massive brain damage that afterwards she was insane.
On the other hand, it must be pretty terrible for the sick person to believe the worst of everyone else and to be so scared of them as to want to kill them. It's a lose/lose scenario from whatever angle you look at it