Police officer Alexander Kozmin has declined to testify in the trial against a participant in last year's large-scale anti-government protest at Moscow's Bolotnaya Ploshchad.
"I did not remember anything, I did not remember faces, I don't know this man," Kozmin said during the Monday hearing, Interfax reported.
The defendant, Mikhail Kosenko, allegedly attacked the policeman during the May 2012 Bolotnaya Ploshchad rally in central Moscow that ended up in clashes with the police and more than four hundred people detained as a result.
Moscow authorities later called the clashes "riots," but in April an unofficial probe conducted by Russian human rights groups at the request of liberal opposition party RPR-Parnas concluded that there were no riots at the rally.
Kozmin has refused to confirm that he was injured by Kosenko, who, according to investigators, is suffering from schizophrenia.
Fourteen rally participants now face criminal charges in what many see as a reaction by authorities to growing opposition activity in the country.
Critics view the proceedings as a show trial intended by the government to spook and sap the morale of opposition leaders.
All of the riot police officers have testified against opposition activists, with observers attributing this to the fact that many of them, including Kozmin, were awarded free apartments by Moscow authorities.
Unlike his colleagues, Kozmin has said he does not think the defendant should be placed in jail and wished him to recover soon. In an interview with Novaya Gazeta the officer said he wants no more involvement in the trial.
