A murder mystery spanning nearly two decades appears to have been solved this week following a killer's confession.

According to Reuters, Dutch national Joran van der Sloot has admitted to murdering Alabama teenager Natalee Holloway while she was on vacation in Aruba.

Killer already in prison for murdering another woman, trafficking drugs

The 36-year-old was extradited to Alabama in June from Peru where he is serving a 28-year sentence for murdering a woman in that nation's capital.

Suspect in Natalee Holloway case to plead guilty to extorting Holloway's mother https://t.co/djytZc2iM4 pic.twitter.com/9Ahr4h9h97

— Reuters (@Reuters) October 18, 2023

What's more, the NL Times reported in 2021 that van der Sloot was sentenced to another 18 years for running a cocaine smuggling operation from his prison cell.

Van der Sloot told U.S. investigators that he murdered Holloway one evening in 2005 after she repeatedly refused his sexual advances while the two were on a beach.

Victim's mother says her daughter's "case is closed"

The killer recalled how after the victim kneed him in his crotch, he responded by kicking her in the head before proceeding to bludgeon Holloway with a cinder block and dump her body in the ocean.

While van der Sloot had originally pleaded not guilty, the convict admitted on Wednesday to killing Holloway as well as attempting to extort money from the victim's mother, Beth Holloway.

"You are a killer and I want you to remember that every time that jail cell door slams," Mrs. Holloway was quoted as saying in court after van der Sloot had entered his plea.

She later told reporters, "Van der Sloot's confession means we've finally reached the end of our never-ending nightmare. Natalie's case is closed, as far as I'm concerned. It's over."

U.S. Attorney Prim Escalona also spoke with journalists, stating, "Today marks the end of 18 years of wondering what happened to Natalee Holloway."

Van der Sloot will be sent to a U.S. prison if he is released or paroled in Peru

For his part, van der Sloot waived his right to an appeal and apologized to the Holloway family, explaining that he has embraced Christianity.

U.S. District Judge Anna Manasco sentenced the defendant to 20 years in prison followed by another three years of supervised release.

Van der Sloot's sentence is to run concurrently with his two Peruvian sentences and he is to be brought to an American prison if he is ever released or paroled at any point over the next two decades.