Dale J. Biederbeck III

Dale "The Whale" Biederbeck was a wealthy financier, and a longtime enemy of Adrian Monk.
History
Background
Arrogant, brilliant, and ruthless, Biederbeck, according to Adrian Monk, owned "half the city of San Francisco, and had a controlling interest in the other half."
Biederbeck's other distinguishing characteristic was his obesity, which gave him his nickname. Though he was apparently obese for most of his life (because of overeating), when he first bought his luxury apartment, he weighed 422 pounds and could still walk (and on a good day, he could see his toes). But after his mother died, he had a complete breakdown. He would call restaurants and order everything on the menu. His physician stated that Biederbeck "topped out" at 927 lbs, though he later decreased his weight to 804 pounds (approximately 360 kilos). He was still unable to walk, leave his bed, or fit through the doorway of his bedroom. Unlike many rich men, Biederbeck went to extreme lengths to avoid publicity (to quote Leland Stottlemeyer, he bought entire newspapers for the sole purpose of "keeping his name out of them").
A few years before she was killed, Trudy Monk wrote an unflattering article about Biederbeck, calling him "the Genghis Khan of world finance." Biederbeck responded by suing her and the newspaper that published the story for libel, knowing that he couldn't win, just to torment her. The suit lasted a whole year, and the legal costs forced the Monks to sell their first home, which Biederbeck snapped up and used as a warehouse for his extensive pornography collection. Adrian Monk called it the worst year of Trudy's life - which would also turn out to be one of her last, since she was killed a short time later. For this reason, Monk hated Biederbeck intensely.
Mr. Monk Meets Dale the Whale
In 2002, Biederbeck became the primary suspect in the slaying of Judge Catherine Lavinio, who had issued a costly antitrust ruling against him. Several clues left behind identified him as the killer, but the police were baffled because he couldn't leave his bedroom. However, Monk eventually deduced that Biederbeck had recruited his personal physician to commit the murder, and then leave clues behind, both to confound the police and to taunt them. In Monk's words, Biederbeck wanted them to know he had done it and gotten away with it, but he didn't. Monk discovered that Biederbeck's physician had done what he did because he was living under a false identity to maintain his business after an accidental death in his practice years before. Dale had discovered this and blackmailed him to the point of owning him. But with his crimes exposed, the doctor readily agreed to cooperate with authorities and relinquish the state's evidence on Biederbeck, who was convicted of murder and sentenced to prison. Before being arrested, he tried to strangle Monk in revenge for foiling his plot, but his immense girth left him unable to reach up to Monk to do so. Monk then took the opportunity to add insult to injury by deliberately leaning towards Biederbeck as he was doing so.
Mr. Monk Goes to Jail
Over the next year, Dale adjusted to life behind bars quite easily. As immobile as ever, he still enjoyed the use of his luxurious furniture, a television, racy photos on the wall, and an inmate to feed him mountains of specially delivered takeout food. A window was scheduled to be added next so that he could watch the sunset, but as they were scheduled to begin construction, a prisoner named Ray Kaspo was poisoned to death less than an hour before his execution. Suspicion fell on Biederbeck, to whom the dead man owed $1,200, and the prison subsequently delayed adding in the window.
Dale was questioned twice before Monk was called to the prison to investigate the case, but upon learning that the victim was scheduled to die anyway, Monk tried to leave the prison and escape its unpleasant atmosphere. Dale put a call to the gatehouse to intercept him and requested to meet. Though the detective was disgusted to meet with him, he acknowledged that Dale would never kill someone for as minor a sum as $1,200. The financier then made Monk an offer that he could not refuse: if he would remain at the prison and solve the murder, Dale would tell him everything he knew about the man who killed Trudy.
In the middle of the case, Stottlemeyer visited Dale to question him. Dale reaffirmed that $1,200 was a paltry sum that he wouldn't bend over to pick up even if he could. He refused to elaborate on the deal he had with Monk, and when Stottlemeyer asked if a window was that important, Dale scornfully replied, "Try living without one."
Monk revisited Dale after solving the case, finding that the window had been installed. Dale briefly teased Monk about whether he had promised him anything before fulfilling his end of the bargain. He revealed two things to Monk: that Trudy was, contrary to Monk's belief, the intended victim of the car bomb, assuaging Monk of his guilt that she took an attack meant for him and that the man he was looking for lived in New York City, his name Warrick Tennyson. Some time later, as a plane headed east, Biederbeck smiled to himself as he was able to see it with his new window musing, "Bon voyage, Mr. Monk."
Monk found and confronted Tennyson on his deathbed, finding that while the dying man was the one who directly killed Trudy by building and planting the bomb, he was not the only one responsible for her death. The only thing that Tennyson could tell Monk about the man who hired him to kill Trudy was that he had six fingers on his right hand.
Unbeknownst to Monk, time would reveal that while Dale had told Monk the truth, it was not the whole truth. Dale not only knew of the six-fingered man already, he also knew the man's identity.
Mr. Monk is On The Run
Over the next three years, Dale managed to become somewhat mobile, albeit through the necessary use of a wheelchair, and he recruited a prison guard, John Rollins, to help him. After the three years were up, he set a plot in motion that would free him from prison, tying it in with a plot that would see Monk arrested in his place. Biederbeck hired Frank Nunn, the six-fingered man, to plant a bomb in a car carrying the Governor of California. With the Governor dead and the Lieutenant Governor already in Biederbeck's pocket, he would be pardoned and return to his comfortable lifestyle. At the same time, Rollins, who was now a police officer, deceived Nunn and left clues for Monk that led the two together. Then Rollins killed Nunn and framed Monk for the crime, sending the detective on the run, with Biederbeck expecting that Monk would eventually be caught, convicted, and imprisoned as he had been.
But Monk foiled his plot, and when Rollins sold him out to minimize his own sentence, Biederbeck lost everything: his furniture, telephone, and laptop were confiscated, his special meal deliveries and manicure appointments were canceled, his window was blocked up, and he was reduced to sleeping in a cramped bunk bed and eating prison food in the cafeteria with the other inmates.
Monk visited Biederbeck, to tell him that Nunn's papers had mentioned a mysterious figure known as "The Judge," who had hired Nunn to kill Trudy. Biederbeck claimed not to know anything about The Judge's identity. Since the Governor had refused to commute Biederbeck's sentence (even before the assassination plot), it was unclear when, if ever, Dale would be eligible for parole. The exposure of his plot and subsequent revocation of his privileges also ensured that his sentence would be that much more punishing. All Dale could do now was try to taunt Monk, saying he was a prisoner of his own personal demons and that he wouldn't trade places with Adrian for "another billion dollars." When Adrian simply ignored him and walked away, Biederbeck was left pathetically yelling for Monk to come back and listen to him, but Monk simply left the prison, leaving Dale to rot.
In 2009, The Judge was finally identified and exposed. It was not made clear whether Biederbeck had ever learned of his identity, but it remained a strong possibility, since his information was good enough to identify Nunn and Tennyson as being connected with her murder.
Trivia and Notes
The name "Biederbeck" is derived from name of the jazz musician Bix Beiderbecke.
In each of his three appearances, a different actor portrayed Biederbeck, each one wearing a fat suit.
Biederbeck is one of the few antagonists to appear in more than one episode, and has the most repeat appearances (3) of any (with the exception of Harold Krenshaw, who is not really an antagonist, but is regarded as one by Monk).
Biederbeck also makes a brief appearance in the non-canon novel "Mr. Monk Goes to Germany," by Lee Goldberg. Monk telephones Biederbeck from Germany when he suspects that one of Dr. Kroger's colleagues, a psychiatrist six-fingers on one hand, is the man who killed Trudy. Since the doctor was giving a lecture at Berkeley in the same week Trudy was killed, thanks to a grant from one of Biederbeck's foundations, Monk suspects Biederbeck of being the killer. Biederbeck smugly refuses to confirm or deny Monk's suspicions, but later Monk proves that the doctor is not Trudy's killer (the novel was written before, but published after, the airing of "Mr. Monk Is On The Run," and Goldberg's foreword acknowledged the discontinuity).
In Goldberg's novel Mr. Monk Gets Even, which takes place in 2012, Biederbeck escapes from custody after undergoing a surgical operation to remove his excess fat, and frames Stottlemeyer as the accomplice to his escape. In the course of the novel, Stottlemeyer refers to him by the new nicknames "Dale the Frail" (when he is left extremely weakened by the surgical procedure) and "Dale the Fail" (after Monk catches him yet again).
The events of the series left open the possibility that Biederbeck knew the identity of The Judge, but ultimately this possibility was not explored.
Just how Monk is considered the Sherlock Holmes of the present-day story, Dale can be considered the James Moriarty to him. Both have brilliant minds and both have experienced grief, Monk with his wife and Biederbeck with his mother, and while Monk's loss destroyed his mind (with obsessive phobic behaviors), Biederbeck's loss destroyed his body (with binge eating).
Dale could also be compared to another Sherlock Holmes villain, Charles Augustus Milverton, from the story "The Adventure of Charles Augustus Milverton". Like Dale, he is a powerful criminal that the protagonist cannot put away due to his reputation. While Dale's money and connections keep him out of trouble, Charles is kept free due to his blackmail on powerful people in London, much like how Dale blackmails Glenn Sindell/Christiaan Vezza into murdering Catherine Lavinio by threatening to reveal his true identity to the FBI.