Bone fragments found during a search in Aruba do not belong to Natalee Holloway, an Alabama teenager who vanished on the island in May 2005 during a high school graduation trip.
Tests on the fragments came back negative for a possible match to Holloway, forensic scientist Jason Kolowski told the Oxygen cable network.
"Out of the four individual bone samples only one was found to be human,” said Kolowski, who led the testing and interpretation of the results for the six-part Oxygen series, "The Disappearance of Natalee Holloway," that aired in August.
The DNA bone sample was ruled out as Holloway after it failed to match to her mother, Kolowski said.
"We don't know if the person is male or female," he told Oxygen. "We don't know how old that person is. We don't know how long that person has been dead."
The identity of the person whose DNA was tested remains unknown, Kolowski said.
Van der Sloot is currently serving a 28-year prison sentence in Peru for killing business student Stephany Flores, who died on the fifth anniversary of Holloway's disappearance in 2010.