Had a look at this. Player is banned now. Don't think video evidence is needed in this case as common sense can be applied here and I trust Niko's judgement on submitting this.
A) The player is laying down on the ground in both screenshots surrounded with nothing but blood, so musta got a good number of rounds into him.
B) The only way the player could have fell over is by getting shot by an enemy. Friendly fire does not allow for team mates to knock each other over.
However, what I will say is that in these cases video evidence kinda is to be preferred. If someone really wanted to create a situation like this, they could punch bug someone, cause them to fall over and desync for about 4-5 seconds and then land a few shots on the player which may or may not sync and then create a screenshot. It is very unlikely to do but it is always a possibility to consider if someone wanted to 'frame' another player.
