MOSCOW — A Russian historian of the Soviet-era system of forced labor camps known as the Gulag is scheduled to undergo enforced psychiatric testing this week, apparently having ruffled some official feathers because of his dedication to unearthing and publishing information about Stalin’s murderous rule.

The historian, Yuri A. Dmitriev, 61, who seemingly ran afoul of the Kremlin’s new emphasis on taking pride in Russia’s past, was arrested in December 2016 on charges of child pornography after taking nine naked photographs of his adoptive daughter, Natalya, then 11.

Mr. Dmitriev denied the photographs had anything to do with pornography, saying that he took them in case social care services accused him of beating her. He faces up to 15 years in prison if convicted.

At the end of December, an expert group found no pornographic content in the pictures, and the court, in Karelia, a region in northwestern Russia, refused to extend his detention beyond Jan. 28.