NEW YORK, Aug 25 (Reuters) - The judge overseeing Viktor Bout's case in Manhattan federal court on Thursday withdrew a previous ruling's harshly critical words against agents who interrogated the suspected Russian arms dealer.

Bout, a former Soviet air force officer who was the subject of a book titled "Merchant of Death," faces charges that include conspiracy to kill U.S. nationals and conspiracy to provide help to a terrorist group. He faces 25 years to life in prison if convicted.

In a ruling issued on Wednesday, U.S. District Judge Shira Scheindlin suppressed statements Bout made to two U.S. Drug Enforcement Administration agents from the Special Operations Division who had helped set-up his capture at a Thai hotel earlier that day in March 2008.

In that ruling, she sided with Bout's account of his post-arrest interview with the agents. But on Thursday, in the revised opinion -- which was almost identical except for the deleted language -- Scheindlin dropped a key footnote that had criticized the agents' version of the interrogation.

The deleted footnote read: "To the extent that the statements in Bout's affidavit are uncontradicted I obviously credit them fully. Based on Bout's uncontradicted description of the events surrounding the arrest, I find his version of the interview more credible than the version advanced by the agents." Other language questioning the agents' credibility was also eliminated.

Legal experts say the removal of the language is unlikely to have an immediate impact on the case, but might have prevented a government appeal or later defense attacks on the agents should they be called as witnesses at this or in other trial.

The judge did not say what prompted her to withdraw her previous ruling, but she explained that her decision on suppressing the statements did not depend on the credibility of the agents.

"Although Bout's account of the treatment he was told he would face in a Thai jail differs from the accounts of the agents, I need not determine which version to credit in order to decide this motion," Thursday's ruling said.

Scheindlin said that when authorities arrested Bout, Thai police denied his request for a lawyer and to speak to a Russian embassy representative. Later, the American officers had likely threatened him with the "heat, hunger, disease and rape" of a Thai jail if he did not cooperate with their questioning.

Bout was extradited to the United States in November to face trial in Manhattan federal court. He had been arrested by Thai police at the Bangkok Sofitel hotel in a sting operation by U.S. agents posing as arms buyers from the Revolutionary Armed Forces of Colombia, known as FARC and considered by the United States to be a terrorist group.

According to court documents, Bout offered to sell the agents advanced man-portable surface to air missiles, as well as approximately 5,000 AK-47 assault rifles.

In court documents, prosecutors have accused Bout of dealing arms since the 1990s to dictators and conflict zones in Africa, South America and the Middle East since the 1990s.

Bout attorney Kenneth Kaplan and a spokeswoman for the Manhattan U.S. attorney both declined to comment on the revised ruling.

The case is U.S. v Viktor Bout, U.S. District Court, Southern District of New York, No. 08-365.

(Reporting by Basil Katz)

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