Twelve years after she mysteriously vanished, new leads are still emerging in the disappearance of Natalee Holloway. Natalee’s father announced Wednesday during an appearance on NBC’s “The Today Show” that new human remains were found in Aruba and were being tested to determine if they were Natalee’s.

Dave Holloway said discovering the remains was the result of an 18-month investigation conducted by him and private investigator T.J. Ward.

“When we determined these remains were human, I was shocked,” he told Today’s Matt Lauer and Savannah Guthrie. “I know there’s a possibility this could be someone else and I’m just trying to wait and see.”

Natalee disappeared in May 2005 during a graduation trip to Aruba with her classmates. She was scheduled to fly home alongside the rest of her group May 30, but never showed up to meet them.

After a grueling worldwide search for the 18-year-old, Natalee was declared officially dead in 2012, but her body was never found. Natalee was reportedly last seen with a Dutch man named Jordan van der Sloot. She reportedly got into a car with Sloot and two brothers named Deepak and Satish Kalpoe at 1 a.m. the last night of the trip.

Van der Sloot was later charged with the death of a business student named Stephany Flores, who died on the fifth anniversary of Natalee’s disappearance. He remained behind bars in Peru, but no one has ever been charged with Natalee’s death.

Her father never stopped searching. He chased down leads left and right until an informant came forward recently to put him in touch with a man who they said had intimate knowledge of Natalee’s death.

“We have a person who states he was directly involved with Joran van der Sloot in disposing of Natalee’s remains,” her father told Today. “I thought, you know, there may be something to this.”

Alongside the private investigator, Dave Holloway headed to Aruba to scour a specific spot provided to them by the informant. It was there that they found the human remains. They are now being DNA tested to see whether they might belong to Natalee. It could take up to a month for the results to come back, her father said.

“We’ve chased a lot of leads,” he told Today. “This one is by far the most credible lead I’ve seen in the last 12 years.”