The 2005 disappearance of Natalee Holloway in Aruba has generated intense coverage and interest for nearly two decades, and the case has once again been reinvigorated. 

On Wednesday, Joran van der Sloot, the Dutch man who has long been suspected in Natalee's disappearance, pleaded guilty in federal court to extortion and wire fraud charges for extorting  Natalee’s mother, Beth Holloway, in 2010, PEOPLE confirms.

In June, Van der Sloot was extradited to the U.S. from Peru, where he was serving a sentence for the unrelated 2010 murder of a 21-year-old woman.

Though van der Sloot’s guilty plea on Wednesday provided new information and a confession to murder, the remains of Natalee — who was declared dead by an Alabama judge in 2012 — have never been found. Here is a timeline of key events in this sprawling case:

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Joran van der Sloot pleaded guilty to extortion and fraud last week in a twisted plot to con money out of the mother of Natalee Holloway, the Alabama teen he has now admitted to killing in Aruba in 2005.

While the plea deal in a federal court in Birmingham, Alabama, did not include murder charges for the slaying on foreign soil, authorities in both countries have indicated that criminal charges could still happen in the island nation.

Natalee Holloway was last seen alive on May 30, 2005, leaving a bar with van der Sloot. He was the prime suspect in her disappearance for the following 18 years and finally admitted to killing her in an Oct. 3 confession made public last week after he pleaded guilty to the extortion case.

JORAN VAN DER SLOOT'S WHIRLWIND PLEA DEAL: ‘HE WON THE GAME,’ BUT FAMILY ACCEPTS CLOSURE

The plea deal required van der Sloot to submit to a polygraph test – which he did. 

He accepted the deal, confessed to killing Holloway on the beach after she refused his sexual advances, and later passed a polygraph test. And he might have got away with it if the Holloway family, supporters, the FBI and an international team of investigators didn't doggedly pursue the case for nearly two decades.

Beth Holloway, Natalee's mother, told Fox News on Wednesday that in addition to the taped confession, the FBI has been able to corroborate his claims. And Judge Anna Manasco said in court that the confession was examined in combination with analysis and evidence by the FBI.

COURT RELEASES RECORDING OF JORAN VAN DER SLOOT'S NATALEE HOLLOWAY CONFESSION

WATCH: Beth Holloway believes Joran van der Sloot's confession of murdering her daughter was 'corroborated'

The polygraph was "just another tool" among many in a broader investigation, an FBI official told Fox News Digital Monday.

"We've been working on this case for 18 years, so there's been a lot of investigative work done over that period of time that was a baseline of our investigation," the official said.

READ MORE ON NATALEE HOLLOWAY FROM FOX NEWS DIGITAL

The officials declined to go into specifics about the rest of that evidence, citing the potential that additional crimes could be under investigation by their counterparts in Aruba. But they said that the FBI, federal prosecutors – and importantly, the Holloway family – had all been satisfied that van der Sloot was being truthful in his recorded confession.

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"After 18 years, Natalee’s case has been solved," Holloway's mother told reporters outside the courthouse immediately after the hearing last week. "Joran van der Sloot is the killer."

As part of the plea deal, Manasco said U.S. prosecutors have agreed not to use van der Sloot's confession against him for any other purposes.

But in Aruba, authorities tell Fox News Digital that their case against van der Sloot is still open, and are requesting investigative documents from the Department of Justice.

"The Holloway case is still an open investigation in Aruba. The Police Force, the Public Prosecutor’s Office of Aruba and other investigative entities will follow up on any serious leads that could solve the disappearance of Natalee Holloway. The search of what happened to her remains unabated," said Ann Angela, spokesperson for the Public Prosecutor’s Office of Aruba. "We have requested the U.S. Department of Justice for all the documents related to the investigation, which we will review before deciding on the procedural steps to be taken against Joran van der Sloot. Up until now, even though we are indeed aware of the reports in the press, we have not yet been formally informed by US authorities."

However, Aruba has a 12-year statute of limitations for charging an individual with murder. Angela told Fox News Digital the issue isn't cut-and-dry.

"Your question as to whether the suspicion against Joran van der Sloot, who at the time of the disappearance of Ms. Holloway was still a minor, is statute-barred or not, cannot be answered with a straightforward yes or no. It depends on various factors within the investigation. As it is an open investigation, the Public Prosecutor’s Office will only provide limited information to the media, also about the issue of the statute of limitation," Angela said. "First things first for us at this moment in time, is to obtain the documents requested to the US Department of Justice."

Van der Sloot will return to Peru to finish a sentence in the mountaintop Challapacla prison for the 2010 murder of Stephany Flores, a 21-year-old business student who he killed in her father's casino. His sentence for the extortion and fraud charges will run concurrently, and once his Peruvian sentence is complete, he will remain imprisoned there for the remainder of his American punishment.

Van der Sloot's lawyer previously told Fox News Digital his client hates the conditions there. Challapalca is known for its nighttime freezing temperatures, and van der Sloot was transferred there after a drug and cellphone smuggling scandal in his former prison. Challapalca is so remote and so high above sea level that there's no cellphone service there, the lawyer said.

GRAPHIC: Read the transcript of Joran van der Sloot's confession (Mobile users go here)

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Van der Sloot had offered shifting explanations over the years for Holloway's final hours over the years, including that he shoved her into a rock, causing a head injury. He has also claimed that his father, a prominent judge who died in 2010, helped hide the body.

In his confession, van der Sloot also said that two friends who were with him on the night of Holloway's death had gone home before the murder.

Satish and Deepak Kalpoe, along with van der Sloot, were arrested and released multiple times as Aruba authorities investigated the case. Island police also questioned Paulus van der Sloot, the killer's father.

Holloway's remains have not been found – however authorities haven't ruled out that one day they may be.

Joran van der Sloot confessed this week to murdering Natalee Holloway in Aruba in 2005, but it’s not clear if he can still be prosecuted in the Caribbean country. 

Aruba has a 12-year statute of limitations for murder, which has already passed. Holloway, 18, went missing while on a senior trip to Aruba in May 2005. Long suspected of having killed her, van der Sloot finally admitted to the murder as part of his guilty plea in U.S. federal court in Alabama for extorting Holloway’s mother, Beth. 

In his confession, van der Sloot — who was 17 at the the time — said he beat Holloway over the head with a cinder block after she rejected his sexual advances, PEOPLE previously reported.

The admission of guilt provides long-sought answers to Holloway’s family, though it’s still possible he will never face charges for the murder itself.

A spokesperson for the Aruba Public Prosecutor’s Office tells PEOPLE that the Holloway case remains an open investigation, and also said the question of whether van der Sloot could still face murder charges in the country in spite of the statute of limitations “cannot be answered with a simple yes or no.”

"The Police Force, the Public Prosecutor’s Office of Aruba and other investigative entities will follow up on any serious leads that could solve the disappearance of Natalee Holloway," the spokesperson said.

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The prosecutor’s office has also requested records from the U.S. Department of Justice related to its investigation, the spokesperson says. The office has not yet been informed by U.S. authorities.

Van der Sloot can’t be prosecuted for the murder in the U.S. The Dutch national was extradited to the U.S. from Peru in June to face charges of extortion and wire fraud after he extorted about $25,000 from Beth Holloway in 2010 in exchange for the promise of information on her daughter’s death, but never gave her answers.

Van der Sloot is currently serving out a 28-year sentence for murder in Peru, after he beat Stephany Flores Ramirez to death in his hotel room on May 30, 2005, five years to the date after Natalee Holloway’s disappearance. 

A judge sentenced van der Sloot to 20 years in prison for the extortion charges, which will run concurrently with his sentence in Peru. If he is released early during his murder sentence, he will serve the rest of the 20 years in the U.S.

While pleading guilty in federal court, van der Sloot apologized to Holloway’s family, but in an interview with NBC, Beth rejected the apology.

“He doesn’t have that in his existence,” she said. “Just to say the words? It’s fine. It didn’t mean anything.”