The mother of missing U.S. teen Natalee Holloway (search) begged authorities Tuesday not to let two Surinamese brothers leave Aruba after they were released as suspects in the probe.

"Do not allow these two ... to enter your country until this case is solved," Beth Holloway Twitty (search) said during a public plea delivered to reporters at the Holiday Inn hotel in Aruba where her daughter was staying before she vanished.

"I am asking this in the name of my beautiful, intelligent and outstanding daughter whom I haven't seen in 36 days," Holloway Twitty urged.

On Monday, a judge ordered that brothers Deepak Kalpoe (search), 21, and Satish Kalpoe (search), 18, be released immediately. A spokesman for the Aruban prime minister told FOX News that the government is powerless to keep the brothers from leaving the island, because they were released without condition.

The Kalpoes' release leaves 17-year-old Joran van der Sloot (search) the sole suspect in this case still behind bars.

Van der Sloot, the son of a justice official, and the Surinamese brothers were arrested June 9 on suspicion of murder in the disappearance of 18-year-old Natalee Holloway, of Mountain Brook, Ala. The judge said the Dutch minor can be held for 60 more days.

Holloway vanished in the early hours of May 30, the last day of a five-day vacation on the Dutch Caribbean island to celebrate her high school graduation with 124 other students.

Contacted by telephone, van der Sloot's father, Paul van der Sloot (search), said he had no comment on the judge's decision.

Prior to the judge's ruling, one of Joran van der Sloot's attorneys, Antonio Carlo, would not say whether investigators had presented any new evidence against his client, but he said a judge did approve a motion allowing attorneys to be present whenever van der Sloot is interrogated.

Carlo said previous motions requesting a lawyer's presence had been denied since the beginning of the case.

"It's important for me to say again today that my client maintains his innocence," Carlo added.

Under Dutch law that governs Aruba, a protectorate of the Netherlands, detainees can be held 116 days before being charged by a judge. Van der Sloot has not been charged.

Prosecutors have acknowledged they have no solid evidence to indicate that Holloway is dead. They have said a murder conviction is possible without a body, but the case requires strong evidence such as a confession, reliable statements and forensic evidence of wrongdoing.

The Kalpoe brothers have told police they dropped Holloway and van der Sloot off near the Marriott Hotel in the early morning hours of May 30 and that that was the last time they saw the blond-haired, blue-eyed teen.

Van der Sloot's mother, Anita van der Sloot (search), said her son told her during a prison visit that he was alone with Holloway on a beach that night but that he did not harm her.

Holloway vanished the same day she was to catch a flight home with her classmates.

Numerous searches by Dutch marines, Aruban investigators and volunteer rescue groups have failed to turn up any trace of her.

Natalee Holloway's mother arrived in Aruba within hours of her daughter's disappearance and has been on the island ever since, distributing fliers, monitoring searches and appearing on national U.S. television shows to keep pressure on investigators.

The Associated Press contributed to this report.