Looks like something unusual surfaced (as on TV),
Air traffic controller who was in charge of the approach/landing says
QUOTE:
I told him "I see you climbing, confirm you are at 900 meters", he replied "Affirm, but we are descending", and continued to climb to 1200 meters. He was too high to make an approach from that position (given 1200 altitude), I gave him vectors (to something) and he accepted the command but did not follow it. I told him to turn right, but he actually turned left. I asked "is it all right with you" and he replied OK. I then handed him over to another controller, but he did not contact (that other controller), and started descending rapidly. At approx 600 meters there was a scream on a radio, and I told him to maintain 600. He did not reply, there was a flash and I declared crash alert. ... he did not report any problem, but was behaving inadequately, did not follow instructions (ATC commands)
Source
Ïåðâûé êàíàë. Îôèöèàëüíûé ñàéò in Russian