Unmasked at last, Christian Gerhartsreiter now has a new identity: inmate number 2800458.
"Which persona did you like the most? Who did you like being the most? Clark Rockefeller?" Moriarty asked Gerhartsreiter.
"Umm, no. No, no, no, no. Let -- let's not get into that again. Erin, Erin, Erin --"
"Well, because we're talking about how you would put on these personas, that it was fun," Moriarty explained.
"Let's go back to the trial testimony. That's why we're here," he said.
Gerhartsreiter, aka "Clark Rockefeller", was serving a four-to-five year sentence for kidnapping his daughter when he was suddenly on the move again. He was hauled from a Massachusetts prison to a California jail, where he would now face charges for the murder of John Sohus.
Los Angeles County sheriff detectives Tim Miley and Delores Scott led the cold case investigation.
"Did you know what you were getting into when you first started this investigation?" Moriarty asked the detectives.
"No. We had no idea how bad it was. How difficult it was gonna get," Det. Miley replied.
"No," Det. Scott said. "It took four years. Four years of our lives, right?"
The detectives had to determine exactly how John Sohus died. The problem was all they had to work with was the victim's skull and it was in pieces and had to be reconstructed by a special lab in Hawaii.
That's when forensic pathologist Dr. Frank Sheridan was finally able to determine how John Sohus had died. He had been viciously bludgeoned.
Asked how he could tell, Dr. Sheridan told Moriarty, "Partly it's based on looking at the edges of the fractures, the dark appearance."
Dark edges, says Dr. Sheridan, mean the fractures occurred at the time of death and not when the body was unearthed.
"Decomposing scalp, blood, can sink down in the fracture lines and that's one of the indications that these fractures occurred shortly before death," he explained.
"How many time do you think John Sohus was hit here?" Moriarty asked, as she and Dr. Sheridan examined the skull.
"In this area here, I believe at least twice," he replied. "... it takes a fairly fair amount of force to cause this kind of injury."
But now, how to prove the killer was Gerhartsreiter? Sohus was buried just feet from the guest house where Gerhartsreiter once lived and his body wrapped in plastic bookstore bags traced to colleges that Gerhartsreiter had attended. Yet no DNA, no fingerprints belonging to the defendant were found.
"But you have to understand that obviously the bags and the body have been underground for nine years ... and dirt just decomposes everything," Det. Scott explained.
"Right, but you've got a jury that might say reasonable doubt," Moriarty noted.
"All we can do is put on the best case we can," said Det. Miley.
In an Los Angeles courtroom in March 2013, Gerhartsreiter went on trial for the murder of John Sohus.
Gerhartsreiter insists he didn't kill John or Linda Sohus. He says Linda is alive. "No. Absolutely not," he adamantly tells Moriarty when asked if he killed Linda Sohus, whose body has never been found. "She's around somewhere."
Gerhartsreiter's defense is that Linda Sohus is the one who killed her husband and is alive and hiding from authorities. The proof: postcards, in Linda's handwriting, that were sent to her family and friends from Europe after she disappeared. But to Walter Kirn, this was classic Gerhartsreiter.
"The postcards were such an ingenious move, you know what I mean? Your common murderer doesn't try to cover a crime that way..." he told Moriarty.
Like a scene from a Hitchcock thriller, Kirn says, the defendant carefully concocted the couple's disappearance.
"To me, one of the most convincing piece of evidence was the stories they told about going off on a secret mission ...going off on a secret mission was a Clark idea," he said. "Now obviously, that was to prepare people not to look for them, to prepare people for their absence."
After nearly three decades, Linda nor her body have been found.
"Isn't it possible that Linda's out there just under a different name doing what Chris did?" Moriarty asked Det. Scott.
"No, everything points to her being deceased," she replied.
Detective Miley says that Linda couldn't have sent the postcards. DNA taken off the stamp doesn't match Linda's, but it also doesn't match the defendant.
"That proves that he has the ability to have someone send a postcard from Europe when he is not there," he explained.
John Sohus' younger sister, Ellen, attended the trial every day and says there is no way that Linda would have killed her brother.
"Linda and John, if you could have seen them together, it would be very hard for you to believe that she would have done anything to hurt John," she told Moriarty.
Ellen says there is far more evidence that points to Gerhartsreiter.
"All the things I learned about how he changed identities, trying to sell my brother's truck, covering up all those things," she said.
"Gerhartsreiter says Didi gave him the truck. You don't believe that?" Moriarty asked.
"No," Ellen replied. "... she didn't touch the bedroom that they slept in. All of his stuff and Linda's stuff was left untouched. She wouldn't have done that and given the truck away."
"This truck was in my possession for three-and-a-half years with its license plates attached, unaltered, unchanged, in excellent condition. Why would a person who is aware of criminal liability preserve evidence?" Gerhartsreiter asserted to Moriarty. "Answer that."
Lieutenant Dan Allen of the Greenwich Police Dept. answered.
"No way, no way," he said. "It wasn't out in the open as far as I could determine. ... no one ever saw that white pickup truck."
And how did he miss someone burying the body right behind Gerhartsreiter's house, when according to trial testimony, it would have taken the killer several hours?
"If Linda in fact killed her husband -- wouldn't you have seen her burying the body? " Moriarty asked.
"Well, if you believe that I am home every single second, that I never leave my house,that I never go out at all, that I don't go away on -- on weekends," he reasoned.
"But wouldn't you notice the ground was dug up?
"It was not a very well-kept property, let's put it that way," said Gerhartsreiter.
As the case goes to the jury, Gerhartsreiter is feeling confident.
"I believe it because I know for a fact that I did not do this. I know that for an absolute fact," he said.
"Sitting in that courtroom ... waves of anger would come over me," Kirn said. "... every minute I was sitting there, I was going 'Please jury ... find him guilty. He did it. He did it.'"