Although I do beleive that the video clearly shows that the congressman took the camera away from the student, it appears that it was somehow returned since
this video was obviously taken off of that phone. However, even if the "thief" returned the phone, it doesn't mean that he didn't steal it. He forcibly removed it from the student's hand and proceeded to walk off with it. I don't know how the student got the camera back since that is not recorded in the video, but it seems obvious to me that he did.