Merritt Rook is the main antagonist of the Law & Order: Special Victims Unit episode "Authority". He was portrayed by the late Robin Williams
A longtime advocate of the proverbial little guy, Merritt Rook began his anti-authoritarian ways at age 13, when he burned down a house in his native Hartford that was being used as a hideout for some local hoodlums and which he claimed had been the site of a rape. When later questioned about this incident, he claimed that he had no choice but to burn the house down, as the boys were shielded by family money and influence. He was arrested for trespassing, burglary, and arson, but these charges were later expunged from his record. For a long time after that, he lived a respectable life as a mild-mannered sound engineer, where he was by all accounts a valued employee. At the high point of his life, he got a steady job with Aerodax Labs, married a singer named Juliet and had a child on the way. There were some signs of his anti-authoritarian leanings (he refused to eat at chain restaurants and only bought locally-grown, organic foods), but he was generally happy and sociable. And then things went wrong. During the birth of his child, Juliet experienced complications, and Rook was told to let an obstetrician, Dr. Francis Slifkin, take charge of the delivery. Slifkin assured Rook that everything would be fine, but Juliet suffered a placental abruption. She and the baby both bled out right in front of Merritt and died as a result. Rook did not take this well, and was summarily removed from the hospital after threatening to kill Dr. Slifkin.
When the police failed to punish the doctor, Rook took matters into his own hands. Using various sound-engineering equipment, he made harassing, threatening phone calls to Slifkin's house, posing as "Officer Milgram". He told Slifkin that he'd gathered information proving that Slifkin had been drunk during Juliet's delivery, and that the doctor would lose his license and go to jail. After weeks of this torment, Slifkin committed suicide.
Perhaps having found some peace, Merritt started to return to his usual congenial self, and even reached the point where he asked a co-worker out on a date, taking her to a jazz club where a friend of his was performing. However, during the date, the friend started playing a song that he'd written with Juliet. Unable to bear this reminder of his beloved wife, Merritt ran out of the club. He decided that the only way he would ever find peace would be to spread a message of anti-authoritarianism to the world.
Shortly after, he took up the persona of Officer Milgram again and made a phone call to a HappiBurger. He told the manager that one of the employees had been stealing, and convinced the manager to call her in and strip-search her. This brought him to the attention of the Special Victims Unit, who managed to gather enough evidence to charge him, despite his using sound engineering equipment to create the false appearance of a trip to Margaretville as an alibi.
In court, Rook served as his own defense attorney, using the trial as a platform to spread his anti-authoritarian views. During his cross-examination of TARU technician Ruben Morales, he drew attention to the fact that the TARU computers relied upon algorithms to enhance the video footage that seemed to link Rook to the phone call, and thus there was a possibility that the algorithm had, through enhancement, made someone else look like Rook. When he cross-examined Det. Elliot Stabler, he questioned whether Stabler had any fingerprints or other physical evidence linking him to the crime, to which Stabler answered that Rook was only identified as the culprit through the enhanced video footage.
Rook's real coup came when ADA Casey Novak brought up the arson that he'd committed years earlier. Rook used this as an opportunity to expound upon the failures of authority to ensure justice.
Much to Novak's horror, the jury found Rook not guilty. As a result, Rook gained a considerable following among the city's various non-conformists and, accompanied by a sheep that he named Elliot, he held a rally celebrating anti-authoritarianism at Bryant Park. However, unbeknownst to him, the police had learned about Slifkin's suicide and during a subsequent rally at Grand Central Station, Det. Olivia Benson attempted to arrest him. However, Rook told her he had a bomb and was prepared to detonate it unless she followed him out of the station.
He took her off to a recording studio where he used to work, and tied her to a chair in a recording booth, claiming he'd rigged the door to the booth so it would explode if anyone opened it. When Det. Stabler arrived, Rook told him he'd attached electrodes to Benson, and told him that he'd torture Benson by pushing a button to deliver shocks unless Stabler pushed the button himself. Stabler refused, despite hearing Benson scream as Rook shocked her, and it was then Stabler admits that it's not in his mind to abuse his own power to hurt others. Sufficiently convinced that Stabler was not a sheep prone to bowing before authority, Rook surrendered to him. He then confessed that the screams were actually pre-recorded, and Benson was never shocked; it was all a test to see if Stabler was a sheep bowing to authority.
However, as the detectives led Rook out of the studio, he activated an ultrasonic trigger that he'd strapped to his leg, triggering an explosion. In the subsequent confusion, Rook fled and was assumed to have dived into the East River - an act which, due to his being handcuffed, probably killed him.