Using thin metal rods and shovels, police and forensic investigators on Friday churned up the earth outside the home of Joran van der Sloot, the last person known to have seen Holloway alive before she vanished nearly two years ago during a school vacation on the Dutch Caribbean island.
"The investigation has never stopped and the Dutch authorities are completely reviewing the case for new indications," Vivian van der Biezen, a spokeswoman for the prosecutor's office, told reporters gathered outside the home.
About 20 investigators arrived from the Netherlands on April 16, van der Biezen said. She said they also searched the home, but she could not say why. They left after a couple hours inside the walled property.
A statement from the prosecutors' office said: "The team has indications that justify a more thorough search."
Holloway, an 18-year-old from Mountain Brook, Alabama, vanished in the early hours of May 30, 2005, the last day of a five-day vacation to celebrate her high school graduation with 124 other students.
She was seen leaving a bar with van der Sloot, then 17, and two Surinamese brothers. The brothers, Deepak and Satish Kalpoe, were jailed and later released after a judge ruled there was not enough evidence to hold them.
Van der Sloot, a Dutch citizen who has been attending college in the Netherlands, was jailed for about three months. He has said he left Holloway alone on a beach after they kissed and he did not harm her.
Calls made to the law office of Paulus van der Sloot, the suspect's father, were not immediately returned Friday.
At least 10 people have been arrested and released without charges. Hundreds more have been questioned.
The Dutch marines, the local coast guard, the FBI, hundreds of volunteers and others have scoured the island's dunes, beaches and trash dumps for Holloway. Scuba divers and sonar-equipped coast guard ships have also examined the seabed.