BIRMINGHAM, Ala. >> The chief suspect in the disappearance of Natalee Holloway has admitted he beat the young Alabama woman to death on a beach in Aruba after she refused his advances. New details in the killing emerged today as Joran van der Sloot pleaded guilty to extorting Holloway’s mother, resolving a case that has captivated the public’s attention for nearly 20 years.

Although van der Sloot isn’t charged in Holloway’s death, his attempt to squeeze a quarter million dollars from the slain teen’s mother gave investigators a crucial link to the 2005 killing. And after finally seeing him in a U.S. courtroom, the family said they’re putting years of doubt and uncertainty behind them.

“As far as I’m concerned, it’s over,” Beth Holloway, Natalee’s mother, told reporters outside the federal courthouse in Alabama. “Joran van der Sloot is no longer the suspect in my daughter’s murder. He is the killer.”

Natalee Holloway went missing during a high school graduation trip with classmates. She was last seen on May 30, 2005, leaving a bar with van der Sloot, a Dutch citizen and student at an international school on the Caribbean island where he grew up. He was questioned in the disappearance but never prosecuted. A judge declared Holloway dead, but her body was never found.

Van der Sloot said in his confession that he pushed her body into the sea.

Now 36, he has pleaded guilty to one count each of extortion and wire fraud in exchange for a 20-year sentence. That prison term will run concurrently with a 28-year sentence he’s serving in Peru for killing Stephany Flores in 2010.

U.S. Judge Anna Manasco said the details of his confession factored into her sentencing decision.

“You have brutally murdered — in separate instances years apart — two young women who refused your sexual advances,” she said.

Shackled and wearing an orange jail uniform, van der Sloot told the crowded courtroom he hoped the confession provides closure.

“I would like the chance to apologize to the Holloway family, my own family,” he said, later adding, “I am no longer the person I was back then.”

Mark White, an attorney for Holloway’s father Dave Holloway, said it his understanding that van der Sloot could not be prosecuted in Aruba — even with his confession — because the statute of limitations has expired.

The judge said the plea deal required van der Sloot to provide all the information he knew about Natalie Holloway’s disappearance, allow her parents to hear in “real time” his discussion with law enforcement, and take a polygraph test.

After the hearing, Beth Holloway told reporters she was “absolutely confident” that they finally got the truth from van der Sloot after years of lies.

Court documents offer a transcript of his confession.

In an interview conducted by his attorney, he says he and Holloway were lying on the beach kissing. She started to resist, but he kept touching her, so she kneed him between the legs. He stood up and kicked her “extremely hard” in the face while she was still lying down.

At that point, he said, she was “unconscious, possibly even uh, even dead, but definitely unconscious.” He said he picked up a nearby cinderblock and brought it down on her face.

Frightened and unsure what to do, he said he dragged her body until he was knee-deep in the waves, then pushed her out to sea.

The Holloway family has long sought answers about the disappearance, and van der Sloot has given different accounts over the years, at one point saying Holloway was buried in gravel under the foundation of a house but later admitting that was untrue.

Five years after the killing, an FBI sting recorded the extortion attempt in which van der Sloot asked for $250,000 from Beth Holloway to tell her where to find her daughter’s body. He agreed to accept $25,000 to disclose the location, and asked for the other $225,000 once the remains were recovered.

Van der Sloot chose “greed over Beth Holloway’s grief,” prosecutor Lloyd Peeples told the judge today.

Van der Sloot moved from Aruba to Peru before he could be arrested in the extortion case. The government of Peru agreed to temporarily extradite him to face trial on the extortion charge, and he will return to Peruvian custody after his case is concluded.

While giving her impact statement today, Beth Holloway turned to stare directly at her daughter’s killer, sitting just a few feet away in court.

“You look like hell, Joran,” she said.