Transcript for German student admits to killing girlfriend's parents: Part 4
Reporter: There's big Ben and Buckingham palace, but in the summer of 1986, there's something else in Britain getting attention. Jens soering and Elizabeth haysom, peering out from their mugshots. American sweethearts and uva scholars on the run from coldhearted murders back in Virginia. Former Scotland yard detectives Ken beever and Terry Wright remember the pair, eager for their weekly court dates. That was their only opportunity to see each other, and I used to let them have a kiss and cuddle in the passageway. Yes, they were definitely still in love. Reporter: In love and in trouble. Virginia investigator Ricky Gardner finally has the captive couple right where he wants then. You flew to London? I did. Reporter: He and the Scotland yard detectives question Jens and Elizabeth about the so called voodoo murder of her parents a little more than a year before. The following statement is being taken from Jens soaring on June the 5th, 1986. Reporter: A strangely compliant Jens waives his right to an attorney and starts talking. Reporter: And he has no lawyer present. That's right. He was questioned for three or four days without an attorney. Presumably that person would have told him to shut up. Reporter: In an extraordinary series of interviews, only some of which were recorded, Jens proceeds to take full responsibility for the killings. Claiming that, Elizabeth stayed behind in Washington creating an alibi with double movie tickets, and room service for two while he drove down to the haysom's home and killed them. He told me that he came at him like this, and he fought like a bear, that he refused to die. Reporter: There is one curious moment during his confession. One that will only become significant later when detectives ask Jens about false confessions. Would you consider pleading guilty to anything that you didn't do? I can't say that for sure right now, but I can see, I can see it happening, yes. I think it is a possibility. I think it happens in real life. Reporter: The detectives do not pursue the point. In her interview, Elizabeth does Jens one better, adding incriminating details, telling the detectives Jens bought a knife before he left to go see her parents, and saying he returned covered in blood. He said to me, I killed your parents. Reporter: Those stunning confessions were enough to get Jens and Elizabeth indicted for murder back in Virginia even while they were still in London. Today we presented indictments for murder. Reporter: Nearly a full year passes before Elizabeth haysom makes her dramatic return to the U.S., landing in the twilight of a may evening in Roanoke. Her hair pulled back in a braid. Her hands cuffed in front. The former university of Virginia student was extradited by British authorities. It's the stuff that TV and movies are made of. The shock that she was involved, wanting to see what she says. It was a very big deal. Reporter: Elizabeth pleads guilty as an accessory-before-the-fact, admitting she helped plan the murders, but insisting Jens is the one who carried out the killings. He had a choice. He had a four-hour drive. No matter what I said to him before that, no matter what I had written to him in months before that, he had a choice, whether he killed my parents or not. Reporter: She is sentenced to 90 years in prison. Meanwhile back in Britain, Jens is fighting extradition, hoping to be tried in Germany where he faces a much lighter sentence, During this extradition proceeding -- Reporter: But it is a losing battle. In 1990 he is finally returned to Virginia. Up until then, we'd only heard Elizabeth's version, and so now, everybody wants to see what he looks like, and hear his version. Reporter: People pack the courtroom expecting drama. And Jens doesn't disappoint. In a stunning turnabout, he takes the stand to now swear he is innocent. Basically Jens was in the position of saying, believe me now. Don't believe that confession I gave a few years ago. We know, Elizabeth, that the most powerful form of evidence in a courtroom is a confession because an average person, a juror cannot -- Reporter: Can't understand. Why would you implicate yourself? Reporter: Jens now says Elizabeth is the one who drove down to her parents' house and murdered them while he stayed behind in Washington. He says Elizabeth, who was using heroin and other hard drugs at the time, came back and told him what she had done. I've killed my parents, I've killed my parents. It wasn't her, it was the drugs that made her do it. Her parents deserved it anyway. You've got to help me, if you don't help me they'll kill me. Reporter: He says his false confession in London was an attempt to take the blame for Elizabeth, to save her from a death sentence. I loved Elizabeth and I believed that the only way I could save her life from the electric chair was for me to take the blame, and that I personally really faced no more than a few years in German prison. His idea, his twisted fantasy was that he would serve his time in Germany, which could be as little as a few years, come out as her hero, and they would ride off into the sunset together. Reporter: Jens' decision to testify however opened him up to a ripsaw cross examination by prosecutor Jim Updike. You have the capability of lying to accomplish a certain goal, don't you? To protect Elizabeth, right. To protect Elizabeth? Yes. Then it would follow if you had the capability of lying to protect Elizabeth, you most certainly have the capability of lying to protect yourself. Correct? That would be logical. Reporter: The prosecutor trying to turn the jury against Jens produces a letter he wrote to Elizabeth, if which he refers to local authorities as yokels. Those yokels don't know what's coming down. I wrote that, yes. Those yokels don't know what's coming down. That's right, I wrote that. I still don't understand -- You still think we don't know what's coming down, don't you? Reporter: The trial features a bitter reunion, Elizabeth arrives from prison, her long blonde hair now shorn, and commits the ultimate betrayal, according to Jens, blaming him for her crime. It suddenly became real. We were going to conspire and commit murder. So much of the case depends on whether the jurors believe Jens soering's story or Elizabeth haysom. Reporter: This was a time before DNA, when blood typing is the best science can do, so the prosecutor makes much of type O blood at the scene. Jens soering has type O along with nearly 40% of the population. The prosecutor also shows the jury a bloody sock-print that he said matches Jens' foot. And you pull that out, and it matches, and it fits like a glove. Reporter: At the end of his three-week trial, the jury doesn't even need to sleep on it. We, the jury find the defendant guilty of first degree murder. Reporter: Jens is convicted and sentenced to life in prison. Get out of the way. Reporter: He has spent nearly every day since fighting to free himself, and now he may be closer than ever. What's up, sheriff? Reporter: Still ahead, in pursuit of truth and justice, what 21st century DNA might reveal.
This transcript has been automatically generated and may not be 100% accurate.