Twelve years after her unsolved disappearance, human remains have been discovered in connection to a search for Natalee Holloway.

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Her father, Dave Holloway, and private investigator T.J. Ward announced on Wednesday's episode of "TODAY" that an 18-month investigation, which was documented for an Oxygen show that airs Sunday, led them to discover the remains, which are currently being DNA tested to confirm if they are indeed Holloway's.

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“When we determined these remains were human, I was shocked,” her father said. “I know there’s a possibility this could be someone else, and I’m just trying to wait and see.”

Natalee Holloway disappeared in 2005 on a post-high school trip to Aruba, and her disappearance has remained a mystery as no one has been charged. Speculation has swirled around Joran van der Sloot, the Dutch man whom Holloway was last seen with at a bar. Van der Sloot is currently serving a 28-year prison sentence in Peru for killing student Stephany Flores on the fifth anniversary of Holloway’s disappearance in 2010.

An informant put the young woman’s father and his private investigator in contact with a man who claimed to have helped van der Sloot hide Holloway’s body. The man claimed Holloway died after being given a date rape drug and was buried in a park. He then led them to the discovery of the human remains.

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“We have a person who states he was directly involved with Joran van der Sloot in disposing of Natalee’s remains,” Holloway’s father said. “I thought, you know, there may be something to this … We’ve chased a lot of leads and this one is by far the most credible lead I’ve seen in the last 12 years.”

The DNA test would take several weeks to a month to determine if the remains are Holloway’s, but her father is looking forward to possibly gaining some closure.

“It would finally be the end,” he said.