Van der Sloot was arrested and released in December before the Holloway case was closed, and the next month a hidden camera caught van der Sloot ridiculing the Aruban authorities that failed to bring charges.
"They have nothing," van der Sloot told van der Eem. "I laughed at them, those investigators. I didn't say a word. I invoked my right to remain silent."
In January, De Vries' team launched a more ambitious surveillance plan involving a Range Rover outfitted with three hidden cameras and a tracking device, as well as several unmarked surveillance cars to observe van der Sloot and van der Eem as they rode around in the Range Rover.
And with the case dropped, it turned out, van der Sloot seemed to open up more about Holloway.
"Will they ever find her, do you think?" van der Eem asked, in one conversation.
"No," van der Sloot said.
"The only thing I still want is a big fat compensation check" for treatment by authorities in Aruba, van der Sloot added. "But before I have it, it'll be 10 years."
"But where … is she, Joran?" van der Eem asked.
"She'll never be found," van der Sloot said.
The day after that January conversation, according to the program, van der Sloot and de Vries appeared together on a Dutch TV show, "Pauw & Witteman," on which de Vries offered theories on van der Sloot's involvement in the Holloway case, and van der Sloot, as he always has, publicly denied involvement.
"If it was proved that you were wrong, would you apologize to me?" Van der Sloot asked de Vries on the show. "Are you man enough to do so?"
"What do you think?" de Vries asked.
"I don't think so," van der Sloot said.
The anger escalated until the end of the show, when van der Sloot famously through a glass of wine in de Vries' face.
"The program was over and I'd just shaken his hand," van der Sloot told van der Eem, according to de Vries TV special. "I look him in the face, and I shake that Pauw and Witteman's hands. I see him looking my way, and I pick up that glass of wine and I just throw it in his face. And he goes, 'Ouch! My eyes! It stings!' And I was so cool. And then you see me going, calmly, like, 'Yeah, I thought you deserved it, you know.'"
De Vries offered another take on the incident.
"I was annoying him. I had questions and I was asking for answers, and he wasn't able to give me answers," de Vries said. "He doesn't have complete control over his behavior."
On his Dutch TV special, de Vries answered van der Sloot's demand for an apology.
"Are you man enough to apologize when we show you literally lied to half the world about what you did that night?" de Vries asked. "You are responsible for the disappearance of Natalee Holloway."
Twitty and Holloway's father, Dave Holloway, have waged a determined publicity campaign in an effort to keep the probe alive and find out what happened to their daughter.
Twitty has published a book about her daughter's disappearance and appeared on Oprah Winfrey's show in January in an effort to keep the search alive.
Police and even army units have combed the island looking for clues to Holloway's disappearance. The most recent search was carried out by oil drilling teams who volunteered their help. They used sonar to search the deep water off of Aruba's coast, but failed to find a trace of Natalee.
Without finding Natalee Holloway's body or a confession from a suspect, prosecutors thought they'd never be able to make a case in Holloway's disappearance. Now, de Vries believes he has "nothing less than a straight-up confession" -- that van der Sloot was with Holloway when she apparently died and a friend of van der Sloot's disposed of the body.