Cohen was a corrupt judge who appeared in the first three episodes of Season 1 of CSI: Crime Scene Investigation.
He had something of a strong gambling problem and regularly used Warrick Brown to place bets on various teams for him in exchange for giving Brown things such as a blank warrant as seen in the pilot episode.
He later forced Brown to begin working for him and in Pledging Mr. Johnson, asked him to break an evidence seal in a rape case in order to compromise the whole thing, thus enabling the rapist to go free.
Cohen claimed that he owned it to the rapist's family to help the attacker escape justice and gave Warrick no choice in the matter.
Eventually, Warrick, distraught turned to his supervisor, Gil Grissom for help in the matter.
Later on, Cohen and Warrick met in a park and thanks to a recording on tape, Captain Jim Brass was able to sweep in with back-up and arrest Cohen, ending the saga once and for all.
Cohen's fate after being arrested is not known but it's presumed that he was disbarred or banned from being a Judge and then eventually jailed.
He was played by Harrison Young.
Corrupt and with a very strong gambling addiction, one that might even outmatch that of Warrick's, Cohen is willing to bend the rules at any cost.
He also has a strong disregard for justice and is more than willing to get someone else to do the dirty work for him while also hoping to continue his errands undetected.
He is also impatient and arrogant, two weaknesses that brought about his own downfall.