I am afraid the last screenshot does not tell anything, like really, it does not tell anything.
@edit: Not that i would do anything about this anyways, i am not an admin xD. i'm just pointing that out...
The last screenshot shows he left.
There is one name missing from the scoreboard so it is not 100% accurate. he could have been that 6th confirmed dead or he could have been in spectate.
The better screenshot is a screenshot of the console with the message of that player disconnecting from the server.
This way you have captured the not only the he left message, but all the chatter that went on beforet hat, it would correlate against what the server logs say if ever there was a dispute. You have better evidence to link someone to that specific time with the chat logs and console logs than you do with a screen cap of the scoreboard. The scoreboard is best to show karma.
I will throw the ban hammer at him though for 4+RDM and leave though.