( CNN ) -- Aruban authorities are urging Natalee Holloway 's father , Dave Holloway , to delay volunteer search efforts in her disappearance until police get better information on the case from Peruvian investigators who have spoken to Joran van der Sloot , prosecutor Peter Blanken said . Police do not want their investigation jeopardized or possible evidence contaminated in the Bubali Bird Sanctuary , a swamp area where Joran once said he dumped Holloway 's body , Blanken said . Aruban authorities wish to search a more focused area once they receive more information from van der Sloot and his laptop , which may include files linking him to the Holloway disappearance . Earlier , Blanken said investigators from Aruba would not be able to question van der Sloot until Peruvian authorities finish their probe of the May 30 slaying of Stephany Flores . The formalities of Peruvian law also will determine the time frame , the prosecutor said . Aruban and Peruvian authorities agreed to `` help each other '' in the Flores case . Van der Sloot , a 22-year-old Dutch citizen , was arrested twice in Aruba in connection with Holloway 's disappearance but released for lack of evidence . Aruba is part of the Netherlands . He said he was in Peru for a poker tournament and met Flores while gambling . Police have said they think van der Sloot killed Flores to steal money she won . Van der Sloot told authorities he attacked Flores on May 30 after she read an e-mail on his computer connected with the Holloway case .
Natalee Holloway 's father wants to search swamp area for daughter 's remains . Authorities want to wait until Peruvian authorities give more information . Aruban investigators will not question van der Sloot until after Peruvians .