Take a look at the video where the perp is down with a cop on him and about 15-20 feet away is another person on his knees with his hands up. Tucker Carlson just had an eyewitness on that confirmed what I saw that there was another person on his knees with hands up. Interesting development.
First I've heard of that. Just guessing, but based on the little you said, could just be someone who happened to be in the immediate area at the time of the take down. They can't take any chances until they sort out who's who.
I think that’s standard practice. The cops tell anybody nearby to put their hands up. When the cops got into the hotel in Vegas, there was a photo of all the slot-machine players standing with their hands up as the police went by...and the police had their guns on these poor freaked out gamblers! But they can’t take any chances.