Police confirmed Monday they were opening an investigation into allegations that the Israel Prisons Service covered up a serious failure that might have prevented a terrorist bombing. Public Security Ministry Comptroller Yitzhak Segev gave police the evidence he had gathered relating to claims that the Prisons Service had doctored a probe on whether a prisoner had offered a key tip-off concerning the April 2006 terror attack at south Tel Aviv's Rosh Ha'ir Shwarma restaurant. Segev concluded it was possibility Prisons Service officers may have tried to tamper with the investigation. After reviewing the case file, Intelligence and Investigations Division chief Cmdr. Yochanan Danino decided to open a criminal investigation into the allegations, assigning the case to the International and Serious Crimes Unit. The suspicions likely center around a daylong probe run by the Prisons Service in March, after a prisoner made public claims that he had offered advance warning of the bombing at the restaurant in which 12 people were killed and more than 60 were wounded. Following the report, the service conducted an internal inquiry led by internal oversight officer Asst.-Warden Dr. Yossi Guber and Dep.-Warden Rami Sela, a member of Guber's staff. The inquiry was launched on March 11, and Sela's and Guber's findings were submitted by 5 p.m. the same day. The findings, the Prisons Service said at the time, reinforced its claim that the prisoner had admitted that he had made up the information. The said that in the course of the one day spent probing the allegations, "Guber and Sela concentrated and gathered intelligence and administrative documents, rules, regulations and orders involved in intelligence work, and met with an intelligence officer related to the matter and met with the IPS's head intelligence officer." But the brief probe left some on the sidelines doubtful that the two officers had conducted a thorough and conclusive probe. Family members of 16-year-old Daniel Wultz, a tourist from Florida killed in the bombing, requested Tuesday that an external probe reexamine whether the service negligently disregarded the prisoner's claims. An attorney representing the family sent a letter to both Public Security Minister Avi Dichter and Prime Minister Ehud Olmert demanding that they establish a new inquiry. Woltz's uncle, Zecharia Schenkolewski, who lives in Jerusalem, said at the time that the family believed that the internal Prisons Service probe was too brief to be thorough, and that Gruber did not even interview the prisoner. "To ask people in the IPS to look into what IPS officers did doesn't seem serious," Schenkolewski said.