Two white-uniformed investigators from Holland on Wednesday also entered the yellow-beige home, which includes an attached apartment where the young man lives, carrying suitcases. They later returned the suitcases to their white, unmarked car.
CBS News Correspondent Kelly Cobiella reports that if the searches in the past two days at the home and a beach have turned up more pieces to fill in the puzzle of Holloways's disappearance, investigators are keeping the details to themselves.
"I can just say because of the investigation, they thought it was a wise move to go there again and again perform a technical investigation," said Mariaine Croes, a spokeswoman for Attorney General Caren Janssen, on CBS News' The Early Show.
Earlier, the Dutch official, Paul van der Sloot, asked a judge for permission to see his 17-year-old son, Joran, who remains in police custody with two other young men in the May 30 disappearance of Holloway, an 18-year-old honors student from Alabama.
Lawyers for the three — Joran van der Sloot and brothers Deepak Kalpoe, 21, and Satish Kalpoe, 18 — also asked a judge to see the evidence against their clients.
The attorney general's office said in a statement the court would rule Thursday on both petitions.
That statement also said a helicopter would "conduct technical investigations" across the island Wednesday night. Calls to authorities seeking further details were not immediately returned.
Croes confirmed to Early Show co-anchor Rene Syler that authorities used thermal sensing equipment to search specific areas last night, but she said that the search did not yield anything.
Holloway was celebrating her graduation from Mountain Brook, Ala., High School with 124 other students and seven chaperones when she vanished. Her U.S. passport and packed bags were found in her room.
Numerous searches by authorities, volunteer islanders and tourists have led nowhere. No one has been charged in the case.
On Tuesday, FBI agents and officers from the Miami-Dade police department used German Shepherds to search a beachside mangrove swamp next to the Marriott Hotel after a former detainee in the case said the three young men may have lied to police about where they took Holloway. The area, known as Malmok beach, is a popular nighttime spot for lovers.
The three initially said they took Holloway to a beach on the northern part of the island but dropped her off at her Holiday Inn, where they claim she was approached by a security guard.
Croes declined to elaborate on the search other than to say it is "part of the investigation." Croes said both towed cars belonged to the family, but she did not say why they were taken away.
Janssen, who also went into the house, declined to comment as investigators wrapped up their search at about 4 p.m. Six police officers guarded the entrance to the property.
Earlier, Paul van der Sloot filed a motion for permission to see his son, while Ruud Oomen, the lawyer representing Deepak Kalpoe, said he filed a motion to force the prosecution to hand over "all the evidence against my client."
In their initial police testimony, the Kalpoe brothers told police they and Joran van der Sloot took Holloway to a beach, and the Dutch youth and the young woman were kissing in the back of the car. The brothers said they then dropped Holloway off at her hotel shortly before 2 a.m. on May 30, when she was approached by a black security guard wearing a black jacket.
"The first time around, they were heard as witnesses in this case," Croes said when asked why the three young men were initially detained by police and then let go.
"When the story of the three boys didn't check out as the investigation went farther, there came a switch from being a witness to being a suspect in this case," she told Syler.
But Antonius "Mickey" John, a former hotel security guard released from custody earlier this week, said Tuesday that while being held in an adjacent jail cell, Deepak Kalpoe told him that story was false.
Deepak Kalpoe told John that he and his brother dropped the young van der Sloot and Holloway off together near the Marriott, about 10 blocks north of the Holiday Inn, John said.
John said he passed the information on to police.
Asked about the alleged conversation between Kalpoe and John, Oomen replied Wednesday, "All I'll say is, my client maintains his innocence."
Paul van der Sloot is a judge-in-training, serving a three-year term on the bench that allows him to hear a limited number of cases.