Hi,
if you make the video go slow enough then you can see smoke coming out of Brian's barrel.
I just went ingame on an undisclosed server and tested both rocket launchers and grenades. There is no smoke after throwing a grenade, or after an explosion of grenade - but there is smoke present here and Brian claims he hit me with a grenade.
I propose increasing the duration of the ban due to how he tries to lie his way out of the situation
Here is the footage in question (RPG/GRE):
if you think it's fake - test it yourself.
On the video you can also see the explosion radius being too big for a grenade (RPG>GRE in explosion radius).
He couldn't have shot any gun before because the smoke would've disappeared - and as he claims, he was walking around with the RPG by denying my accusations of him firing the rocket and saying that it happens after walking around with a rocket launcher as well. (which is true but then it means he was walking around and he had no time to fire a gun before)
This is very clear on the technical level.