Polish officials investigating a now-shuttered secret CIA prison in this country have given a Saudi terror suspect victim status, a legal advance in the detainee's effort to show he was mistreated by interrogators, officials said Wednesday.Legal experts said Poland's move to grant the status of victim to Abd al-Rahim al-Nashiri recognizes the validity of his claims even as US courts have refused to allow cases involving rendition to move forward for national security reasons.Al-Nashiri, a Saudi national accused in the 2000 bombing of the USS Cole warship in a Yemeni harbor, was apprehended by the US, taken to secret CIA prisons in Poland and Thailand and subjected to harsh treatment, according to former US intelligence officials."While this is a significant step forward, it remains to be seen whether the Polish prosecutor will push forward seriously with the investigation," said Amrit Singh, a senior legal officer for the Open Society Justice Initiative.Polish officials in power when the prison was in operation still deny its existence but al-Nashiri's victim status weakens their position — and it raises the prospect that some could eventually be charged with abuse of power.The Polish prosecutor guiding the investigation, Jerzy Mierzewski, told The Associated Press that al-Nashiri has been given victim status, and that the move "entails a number of rights for the injured party." He wouldn't divulge any other information, citing the secret nature of the investigation.Adam Bodnar, a lawyer and activist with the Helsinski Foundation for Human Rights in Warsaw, said that al-Nashiri's victim status will give his lawyers the right to participate in proceedings, a practical advantage. The move, he said, also indicates that prosecutors believe there is mounting evidence to support al-Nashiri's claims."Granting such a 'victim status' means that the prosecutor's office is to a great extent convinced of the argumentation that he was rendered and held illegally on the territory of Poland," Bodnar said. "So basically it's an indirect acceptance that the arguments and facts presented by the lawyers are probable. It doesn't mean they are true — but that on balance there is the probability."According to a motion filed in Poland last month, al-Nashiri's lawyers have asked Polish prosecutors to call several former top CIA directors to testify as well as pilots of the various flights that ferried the suspects in and out of Poland.Former US intelligence officials have said the spy agency operated the site code-named "Quartz" in northern Poland from December 2002 to the fall of 2003. Human rights activists and lawyers for al-Nashiri say their client was tortured in Poland and denied a fair trial for nine years.Imprisoned at Guantanamo, he's accused of masterminding the October 2000 attack on the U.S. destroyer off the cost of Yemen that killed 17 American sailors.Prosecutions of any Polish officials who allowed the site to operate on Polish soil would bring al-Nashiri a measure of justice in his case, activists and the detainee's lawyers say."I'm very satisfied with the prosecutor's decision to admit al-Nashiri to the investigation as a victim," Mikolaj Pietrzak, al-Nashiri's Polish lawyer said. "I expect the case to end with indictments against those responsible for the illegal detention and torturing of al-Nashiri."He added: "It means there is a chance that the Polish investigation will actually serve to vindicate al-Nashiri's rights."The CIA, saying the program is a thing of the past, is trying to focus on preventing future terrorist attacks.Al-Nashiri's lawyers believe he hasn't been tried yet because he was subjected to waterboarding and other harsh interrogation techniques in Poland and Thailand, making any evidence obtained at the black sites legally problematic to introduce in a court of law.The investigation in Warsaw was launched by the Polish government two years ago in reaction to massive pressure from the European Union and the Council of Europe, a human rights group. Both organizations have said that evidence points to the complicity of Poland as well as Romania in the clandestine US program, and they have urged both ex-communist nations to clarify the matter.Former US intelligence officials have told the AP that Al-Nashiri was captured in Dubai in November 2002 and taken first to a secret CIA prison in Afghanistan known as the Salt Pit. After a brief stay, he was flown to a CIA prison in Thailand and then transported to Poland on Dec. 5, 2002, along with accused terrorist Abu Zubayda, the former officials said.According to the former intelligence officials and an internal CIA special review of the program, al-Nashiri was subjected to harsh interrogation methods. They say that an agency officer named Albert revved a bitless power drill near the head of a naked and hooded al-Nashiri while he was held in the Polish prison. The CIA officer also took an unloaded semiautomatic handgun to the cell where al-Nashiri was shackled and racked the weapon's ammunition chamber once or twice next to his head, according to the review.The US officials spoke about the prison and al-Nashiri's case on condition of anonymity because details of the secret program remain classified. The details of where the incidents took place and who was involved were first reported by the AP in September.According to the former officials and flight records, al-Nashiri was moved from Poland to Rabat, Morocco, on June 6, 2003, and then moved repeatedly to and from CIA sites in Guantanamo, Rabat and Romania until he was finally returned to Guantanamo in September 2006.Al-Nashiri's case is in limbo as the White House decides whether to prosecute him in a U.S. military or a federal civilian court.