How were they to know he was dead? Just because some people from the Internet said so?
By the same method that the "people from the Internet" knew; he had a bloody webcam on him the whole time!
If they weren't sure he was dead, why not bring the paramedics? I don't understand the guns, either. What's that all about? And why point them at him?
There's something very wrong with a country in which (b) two planes hit a couple of skyscrapers in broad daylight before thousands of witnesses but a bunch of people start denying that it actually happened, and (b) a guy commits suicide on his webcam with full video footage of the event (and the webcam still running when the cops arrived) but the cops respond by bursting into the dead guy's room, throwing something at his corpse and threatening it with loaded firearms.
I wonder how they deal with the victims of car accidents?
"Put your hands on your head and step out of the vehicle please, sir".
"My legs are broken and my arms are trapped beneath the steering wheel!!!"
"If you do not comply I will be required to use force sir, now step out of the vehicle please..."
And so on and so forth, with predictable results.