MOSCOW - In a potentially crucial turn for a contentious criminal trial, two forensic psychiatrists testified yesterday that Yuri D. Budanov, a colonel in the Russian army, was insane when he strangled an 18-year-old Chechen woman nearly three years ago.

The psychiatrists' judgment of insanity - the second such opinion in months - appeared to pave the way for Budanov's acquittal in a court proceeding that has become a yardstick for Russia's ability or willingness to control human rights abuses by members of its military.

Budanov's lawyer immediately said he would ask the judge in the trial to dismiss the charges and order psychiatric treatment for his client, possibly as soon as Friday, when the trial is scheduled to resume.

Some human rights activists said the testimony raised old doubts about the impartiality of the trial, which has long been dogged by charges that evidence of Budanov's guilt had been altered or suppressed.

Budanov, once a commander in the army's 160th regiment, has admitted that he seized the woman, Elza Kungayeva, from her home in Chechnya in March 2000.

He said he later cut off her clothes with a knife and strangled her on a cot in the tent that served as his quarters. He had been drinking heavily before killing her.

His lawyers argue that he murdered Kungayeva in a fit of passion because he believed she was a sniper who had murdered several of his troops. Kungayeva's relatives say he raped her, a contention backed by an autopsy report that was later recalled and changed. They also say her murder was premeditated.

The Kremlin initially expressed outrage over the crime and even dispatched a representative to Kungayeva's funeral. But many in the Russian military have closed ranks behind Budanov, and opinion polls have suggested that most ordinary Russians believe he should be set free.

Court-appointed psychiatrists said this summer that Budanov was insane at the time of the murder. Some outside experts question this opinion because several aspects of the killing, such as the colonel's subsequent order to subordinates to hide her body, indicate that he knew he had committed a crime.

The federal health ministry ordered Budanov re-examined this fall at Russia's Serbsky psychiatric institute.

This highly unusual move suggested to some outsiders that the Russian government was concerned about the objectivity of the trial.