Joran van der Sloot has confessed to having killed Natalee Holloway in 2005. 

The 36-year-old van der Sloot, according to Fox News, made the confession in documents that were filed with the court on Wednesday.

In court, Van der Sloot, according to the outlet, also apologized to Holloway's family, and he agreed to help the family and law enforcement with the case going forward.

This is all part of a plea agreement that van der Sloot appears to have reached with the prosecution.

As part of the agreement, the Dutch national has pled guilty to extorting money and wire fraud, two charges that are related to the murder of Holloway. Van der Sloot also has agreed to provide information about Holloway's murder.

In May 2005, the 18-year-old Holloway went missing during a high school class trip to Aruba. She was last seen exiting a bar with van der Sloot. After a lengthy investigation failed to discover her whereabouts, she would be declared legally dead in January 2012.

In 2010, van der Sloot attempted to extort money from Holloway's mother, Beth Holloway, in exchange for information about the location of her daughter's body. This is what led to the extortion and wire fraud charges, to which van der Sloot has now pled guilty.

In his newly made confession, van der Sloot reveals what really happened to Holloway. It appears that van der Sloot killed Holloway, in anger, after she rejected his sexual advances. He says that he crushed her head with a cinderblock.

"I smash her head in with it completely," van der Sloot said, adding, "Her face basically, you know, collapses in. Even though it's dark, I can see her face is collapsed in."

After that, van der Sloot says that he dragged Holloway's body into the water until the water reached his knees. He then pushed her out to sea, and went home.

Outside of the courthouse on Wednesday, Holloway's mother said, "After 18 years, Natalee’s case has been solved. Joran van der Sloot is the killer."

Van der Sloot has also been ordered to immediately pay $25,100 in restitution to Holloway's family, and he has been sentenced to 20 years of imprisonment.

He is getting credit for the time that he has served thus far, since being brought to the United States in June. Accordingly, van der Sloot's expected release date is now June 9, 2043.

Van der Sloot is also serving a prison sentence for the 2010 murder of Stephany Flores Ramirez, which took place in Peru.