Satish and Deepak Kalpoe were arrested on suspicion of involvement, with unidentified "other people," in premeditated murder and rape, Aruba's prosecutor's office said in a statement.
To arrest them again, "there had to be new facts and circumstances. That is the case," the statement said. Authorities declined to disclose any other details of the new evidence.
The prosecutor's office also said the brothers were suspected of other offenses, but they did not provide details. No information was disclosed about a third man who authorities said was arrested Friday with the Kalpoes.
A judge later ruled that prosecutors had enough evidence to hold the three men for at least eight days while they build their case, said Elgin Zeppenveldt, a lawyer for Satish Kalpoe.
"We are appealing the decision, because the prosecution is withholding documents from us," Zeppenveldt said.
Satish, 18, and Deepak, 21, Kalpoe were released from jail in July after a judge ruled there was not enough evidence to hold them in the disappearance of the 18-year-old American, who vanished the final night of a high school graduation trip to the Dutch Caribbean island.
Their release was one of a series of apparent setbacks in the case that have included discoveries of possible physical evidence or witnesses that later turned out to be false leads.
The brothers were first arrested on June 9 along with Joran van der Sloot, 18, who authorities have identified as a suspect in the case though no charges have been filed.
Meanwhile, CBS News Correspondent Kelly Cobiella reports that in Holloway's hometown of Mountain Brook, Ala., people haven't given up hope that she will be found. On Thursday night,to raise money for the family.
Over 200 items were donated by celebrities for the auction that was the idea of Courtney Cox, who graduated from the same high school as Holloway, Cobiella reports.
Holloway's family said they were pleased about the arrests, which they learned about from the FBI.
"We haven't been told why, but I think it's obvious," Natalee's stepmother, Robin Holloway, said by phone from Meridian, Miss. "We've known all along they had something to do with Natalee's disappearance."
Holloway, of Mountain Brook, Ala., was last seen leaving a bar with the Kalpoe brothers and van der Sloot in the early hours of May 30. Extensive searches of the island have produced no sign of the teen who was last seen in public leaving a bar with van der Sloot and two other young local men.