After St. Louis police shot to death 25-year-old Kajieme Powell yesterday (as mentioned in Elizabeth Nolan Brown's post below)—and apparently for good measure cuffed his corpse, says an eyewitness at the scene of the video below around 2:45—St. Louis Police Chief Sam Dotson told the press that he was a clear and present danger to the officers, having, as the St. Louis Post-Dispatch reported, "pulled out a knife and came at the officers, gripping and holding it high, Dotson said." The Huffington Post reported Dotson as saying the knife was in an "overhand grip."
This cell phone video—alas from pretty far away—does not look to me like Powell was raising his arms. Nor does it show any obvious sign that I can see of a knife at all, but I can't be sure of that. But the position of his arms seems clear enough to me when the shots that killed him begin, around 1:35 or so of the video.
The video. Yes, it's disturbing: