A CELEBRITY DOG TRAINER MURDERED, AN HEIRESS FEARING FOR HER LIFE AND A BODYGUARD DETERMINED TO BE A HERO -- NOW, THE CONCLUSION OF A SPECIAL TWO-PART BROADCAST OF "48 HOURS MYSTERY," TO BE BROADCAST ON SATURDAY, FEB. 12 ON THE CBS TELEVISION NETWORK

For friends and family of Mark Stover, the beautiful landscape of the Pacific Northwest holds a secret that haunts them. Mark was known as the Dog Whisperer of Anacortes - a dog trainer to the stars, who counted rock stars, professional athletes and CEOs among his high-profile clients. But on the morning of Oct. 28, 2009, one of Stover's employees entered his Anacortes, Wash., home to find his guard dog, Dingo, missing and the only sign of her owner were drops of blood in the house. There was one inescapable conclusion - Mark Stover had been murdered.

On Saturday, Feb. 12 (10:00-11:00 PM, ET/PT) 48 HOURS MYSTERY will broadcast the conclusion of its special two-part program, "The Dog Trainer, the Heiress and the Bodyguard," featuring an exclusive interview with the heiress at the center of it all. Correspondent Peter Van Sant delves into the mysterious love triangle that some believe was at the heart of this murder, and Stover's troubled past that raises the question - just who is the real villain in this story.

On the morning of Stover's disappearance, two women reported seeing a man moving a large object from one car into a black SUV. One of the vehicles was Stover's missing car. Authorities pulled the SUV over for trespassing. The driver was a man by the name of Michiel Oakes.

Oakes, a single father to four children, was a weapons expert who also specialized in hand-to-hand combat. He advised Linda Opdycke, who had been married to Stover, after she claimed he was stalking and threatening her. Fearing for her life, this damsel in distress found her hero in Oakes and a romance soon blossomed.

Before he vanished, Stover seemed to have finally moved on from his past with Opdycke, developing a new relationship with a woman he hoped to marry. But Oakes says that Stover still posed a threat, now stalking him and threatening his children. He admitted to authorities being at Stover's house the morning he disappeared, but not to murder the successful dog trainer. According to Oakes, Stover called him to meet at the house, then pulled out a pistol and pointed it at Oakes' chest. Stover's death was an act of self-defense, claims Oakes, who also admits that he put Stover's lifeless body in the back of his SUV and got rid of it. But did he act alone? Investigators were now turning their attention to Opdycke, the heiress from one of the most powerful families in the state of Washington, who maintains that she knew nothing about the crime and has never been charged.

Was Michiel Oakes a bodyguard protecting his family against a threat? Was he acting on his own to protect his newfound love? Or, was he an assassin, hired in a plot hatched by Mark Stover's ex-wife? Only two people know what happened inside Stover's house - one is dead and the other is about to take the stand in a trial that would put everything on the line. And it would be up to a jury to decide who is to blame in the death of the Dog Whisperer of Anacortes.

Click here for an extended preview of part two of 48 HOURS MYSTERY "The Dog Trainer, the Heiress and the Bodyguard," to be broadcast on Saturday, Feb. 12, (10:00-11:00 PM, ET/PT). This broadcast is produced by Liza Finley, with Marcelena Spencer and Sara Rodriguez. Ryan Smith is the field producer. Peter Schweitzer is the senior producer. Al Briganti is the executive editor. Susan Zirinsky is the executive producer.