The harsh terrorist interrogation techniques of the US, such as waterboarding, did not provide any key evidence that led to finding and killing of Osama bin Laden, a new senate report is expected to claim.

The new report about the use of torture methods by the CIA in the years after 9/11 is still kept a secret. But the findings of the 6,200-page senate report were revealed to the Associated Press by congressional aides familiar with the project, the Pakistan Observer stated.

If it is confirmed that the disturbing interrogation techniques did not actually lead to the capture for bin Laden, it will be a direct challenge to the assertion by the former members of the George W Bush administration that the CIA's so-called 'sophisticated' interrogation methods were an essential tool in busting the world's most famous terrorist.

The congressional aides, familiar with the still-secret senate report, reportedly said that as per a review of some 6 million classified documents, it was concluded that there was no benefit derived from treatments that the United Nations and several human rights groups have defined as 'torture'.

The news of the leaked report comes as the US Senate's powerful intelligence committee is due to hold a vote on Thursday, on whether to release a 400-page summary of the aforementioned report. The vote is then expected to set in motion a declassification process that could ultimately make the entire report public within several months.

The findings of the report has already caused bitter rifts between Diane Feinstein, the Committee's democrat chair, and the CIA, whom she has openly accused of trying to repress the publication of the findings since they were approved in December 2012.

The most important findings are expected to be that the harsh treatment meted out to the Al Qaeda suspects, held in places such as Bagram Airbase in Afghanistan, the Guantanamo Bay detention centre and black jails around the world, which did not really lead to a critical intelligence that ultimately helped in killing bin Laden.

The enhanced interrogation techniques, authorized by the former Bush administration and top CIA officials after the September 11 attacks, were claimed to have played a key role in the killing of the Al-Qaeda leader.

Among the key points of contention in the report was the treatment of Kalid Sheikh Mohammed, the man accused of masterminding 9/11. He was waterboarded 183 times.

The CIA had claimed that they ultimately traced bin Laden after Mohammed had confirmed that he knew an important Al-Qaeda courier with the nom de guerre Abu Ahmed al-Kuwaiti. However, the senate report says that information was not critical and was known even before Mohammed was tortured.