Oranjestad, Aruba ? A disc jockey on an Aruban tourist party boat was detained Friday in the disappearance of Alabama teen Natalee Holloway, making him the fourth person held by police since the honors student vanished last month.

Meanwhile, Holloway’s mother said she believed there might be more arrests before the case was resolved, although she expressed increasing frustration with the pace of the investigation. Beth Holloway Twitty also held onto hope that her 18-year-old daughter, last seen May 30, was still alive.

Steve Gregory Croes, 26, whom authorities earlier identified only by the initials S.G.C., said he was contacted by police Thursday night and voluntarily gave a statement, said his employer, Marcus Wiggins.

Croes also said he knew one of two Surinamese brothers being detained in the case because they went to the same Internet cafe, Wiggins told The Associated Press.

Croes was a DJ on the Tattoo, which offers nightly dining, dancing and swimming, Wiggins said.

“I’ve never had problems with him,” Wiggins told the AP. “He keeps to himself and shows up to work every day and does his job.”

In Alabama, a woman who helped organize the graduation trip, Jody Bearman, said students did not go on the Tattoo as a group, but some could have taken a boat ride without the seven adult chaperones knowing.

Authorities previously detained 17-year-old Joran van der Sloot, the son of a Dutch justice official on Aruba, and his two friends, Surinamese brothers Deepak Kalpoe, 21, and Satish Kalpoe, 18. No one has been charged in the case.

Police Supt. Jan van der Straaten refused to identify the fourth detainee but told the AP he was detained based on information from one of the other three.

Holloway disappeared in the early morning hours of May 30 on this Dutch protectorate in the Caribbean. The three men detained earlier said they took Holloway to a northern beach but dropped her off at her hotel, where she was approached by a security guard.