None have been officially charged with a crime, but they were arrested on suspicion of voluntary manslaughter, a lesser crime under Aruban law than murder, which requires proof of premeditation.
The detentions, which must be reapproved by a judge, periodically, depending on the number of detentions, are meant to allow authorities access to the suspects as they work to build a case strong enough to take to trial.
Van der Sloot's attorneys insist the restrictions on their client are unreasonable. He is not allowed family visits or access even to his American attorney, Joseph Tacopina. He is also restricted from access to newspapers, magazines, television and a Bible, Tacopina told ABC News.
To a greater degree than the Kalpoe brothers, Van der Sloot has been the subject of intense police scrutiny, repeatedly detained, and later released, and made to "re-enact" the evening he spent with Holloway, several times.
His lawyers say he has always been cooperative with the investigation. On Dec. 7, they hope to persuade a judge, based on those facts, to at least release the young man to house arrest with an ankle bracelet monitor. His parents own a home on the island.
As media anticipation of the Holloway parents' return to the island builds through a week that has provided few verifiable developments, but enough intriguing rumors to keep the news-starved press chasing mostly specious ghosts of truth from one end of the island to the other, another curious endeavor is under way.
More than 2½ years after Holloway's disappearance from Aruba, another large-scale, high-tech private search operation is planned for this weekend.
The Texas Equusearch Mounted Search and Recovery Team — which has searched waters off Aruba five times since Holloway's disappearance — departed last week from a Louisiana port for the lengthy ocean journey to Aruba. Using a 125-foot vessel with sophisticated side-scanning sonar that can detect objects 600 feet in two directions, the clearly determined team will probe the deeper waters further off the coast surrounding the island.
While few would dispute the enormous odds against summoning up any new forensic clues from the nebulous ocean tides, so long after Holloway's disappearance, hope — even seemingly unrealistic hope — is a privilege and a right most observers would surely grant a father whose daughter vanished without a trace.
"You know, that's important for any human being to have closure, and know exactly what happened, and have, you know, funeral burial," Dave Holloway told ABC News affiliate KIRK last week.
"I'm very, very optimistic that we're going to be going to a funeral in Birmingham, Ala., before long," he said.