WASHINGTON - A human rights group on Tuesday asked US President Barack Obama to order a criminal investigation into allegations of detainee abuse authorized by former President George W. Bush and other senior officials.

In a 107-page report entitled, "Getting Away with Torture: The Bush Administration and Mistreatment of Detainees," the Human Rights Watch (HRW) said overwhelming evidence of torture by the Bush administration obliges Obama to issue such an order.

"There are solid grounds to investigate Bush, (former Vice-President Dick) Cheney, (former Secretary of Defense Donald) Rumsfeld, and (former CIA Director George) Tenet for authorizing torture and war crimes," said HRW Executive Director Kenneth Roth. "President Obama has treated torture as an unfortunate policy choice rather than a crime."

The Bush administration -- the CIA in particular -- has been under strong criticism for its mistreatment and abuse of prisoners after September 11. Documents showed the CIA had employed "enhanced techniques" to varying degrees, including stress positions, extreme temperature changes, sleep deprivation and "waterboarding" in the interrogation of some detainees.

"The US has a legal obligation to investigate these crimes," Roth said. "If the US doesn't act on them, other countries should."

The human rights watchdog criticized the Justice Department for its limited scope in investigation into potential detainee abuse.

"In August 2009, US Attorney General Eric Holder appointed Assistant US Attorney John Durham to investigate detainee abuse but limited the probe to 'unauthorized' acts. That meant the investigation could not cover acts of torture, such as waterboarding, and other ill-treatment authorized by Bush administration lawyers, even if the acts violated domestic and international law," it said.

The Justice Department wrapped up last month its preliminary investigation into the matter, concluding that a full criminal probe was only necessary in the case of two deaths in custody.