An English tutor from New York, living in Russia, has been accused of child rape and pornography offences involving two girls under the age of 14.
Long-term expat David Lang, 64, who teaches English and business classes in Chelyabinsk, faces 25 counts of rape, producing child pornography and sexual abuse charges over the course of nine years.
Lang, a respected teacher known to senior US diplomats, could face 15 years in jail, if convicted.
His trial - in the Urals city of Chelyabinsk, where he lived - is being held in secret because of the underage victims.
Evidence at his trial will include graphic pictures and films reportedly to seized at his home in Chelyabinsk or posted on the internet.
A spokesman for Kurchatovsky District court said: 'The first hearing took place on September 6.
'The man was charged with making and distributing pornographic materials where underage children were involved.
'He is also accused of raping underage victims. There are two victims in the case.
'The hearings are closed because of the underage victims.'
The names of the children have not been given, nor have their ages when the offences took place, except that they were under 14.
Lang was detained in 2015, and has been held since at a detention jail in Chelyabinsk.
Before his arrest the accused was pictured with then US ambassador to Russia, Alexander Vershbow, who served in Moscow from 2001 to 2005.
He was also photographed with American consul-general in Ekaterinburg, Thomas Niblock.
It is believed Lang took part in US programmes to develop democracy in Russia.
Lang has been living and working in Russia since the early 2000s, say the authorities.
According to state investigators, Lang posted his child pornography online and his illegal activities went on from June 2006 to November 2015 when he was arrested.
The Russian authorities were earlier reported to have accused Lang of overstaying his visa.
US teacher ‘filmed himself raping and abusing young schoolgirls in Russia and posted the footage online’ Will Stewart for MailOnline 18 September 2017