Human Rights Watch released a report Tuesday calling on the Obama administration to reopen criminal investigations into senior U.S. officials, including former President George W. Bush, for their involvement in the post-Sept. 11 CIA torture program.

"It's been a year since the Senate torture report, and still the Obama administration has not opened new criminal investigations into CIA torture," said Kenneth Roth, executive director of Human Rights Watch. "Without criminal investigations, which would remove torture as a policy option, Obama's legacy will forever be poisoned."

After the Senate Intelligence Committee released a still-classified 6,700-page report on the brutal torture program last year, the Justice Department stood by its previous decision from 2012 to not prosecute anyone involved, saying that there was insufficient admissible evidence to sustain convictions beyond a reasonable doubt.

But Human Rights Watch says that included in its 153-page report is ample evidence that the attorney general can in fact order a criminal investigation into Bush and 20 other former Bush administration officials for torture, conspiracy to torture and other crimes, reported Reuters.

The other officials include former Vice President Dick Cheney, former CIA Director George Tenet, former U.S. Attorney General John Ashcroft and National Security Adviser Condoleeza Rice.

Much of the Human Rights Watch's evidence was drawn from the 500-page executive summary of the Senate report, which revealed previously undisclosed details of mistreatment of suspected terrorists imprisoned by the CIA, including waterboarding, rectal feeding, stress positions, sleep deprivation and other painful techniques, according to the Los Angeles Times.

The Senate report concluded that the interrogation techniques only led to false confessions and fabricated information and produced no useful intelligence on imminent terrorist attacks.

While much of the torture program took place more than a decade ago, Human Rights Watch said the usual five-year statute of limitations on crimes of torture could be extended because there was a "foreseeable risk that death or seriously bodily injury" may occur. The statute of limitations for conspiracy charges can be extended if a central component of the plot was concealed, according to the group.

"Under the United Nations Convention against Torture, which the United States ratified in 1988, governments are required to credibly investigate allegations of torture and to prosecute where warranted," the group said. "The failure to investigate and prosecute CIA torture increases the danger that some future president will authorize similar illegal interrogation methods in response to an inevitable serious security threat. Several presidential candidates for the 2016 elections have defended the use of 'enhanced interrogation techniques' and some have said they would use them again if elected."