Because a good professional police department don’t go off half cock and release information that hasn’t been thoroughly checked double check swore proven and investigated. Their job is NOT to provide headlines! Their job is to establish FACTS. Unfortunately you can not do such a thorough investigation at the speed of half-truths, innuendo,supposition and out right bald-face lies that the media is more than willing to print and the race-baiters more than willing to spread.
Why did the sheriff say the guy was shot from 35 feet?
Well, sure. But either a radio call went out saying there was a strong-arm robbery, and someone fitting Brown's description was a suspect, or such a call didn't go out.
How long would it take to check for sure? A couple of hours at most.