A Russian scientist who was arrested on suspicion of state treason and flown to Moscow despite being "on his deathbed" has died, according to lawyers and a family member.
Physicist Dmitry Kolker - a laser specialist - had been suffering from advanced pancreatic cancer and was taken from his hospital bed in Siberia, where he was being fed through a tube.
He was bundled onto a flight of more than four hours to Moscow, where the lawyers said he was taken to Lefortovo prison before he later died in a nearby hospital.
The 54-year-old had been accused of betraying state secrets to China.
His cousin Anton Dianov said the allegations against the scientist had been "absolutely ridiculous".
He said: "He was a scientist, he loved his country, he was working in his country despite many invitations from leading universities and labs to go work abroad.
"He wanted to work in Russia, he wanted to teach students there.
"These charges are absolutely ridiculous and extremely cruel and unusual to be levied on such a sick man.
"They knew that he was on his deathbed and they chose to arrest him."
'Treason charges were based on lectures'
The family and lawyers said Mr Kolker was detained and his house searched by the FSB security service.
They said the treason charges - which carry a sentence of up to 20 years - were based on lectures he had delivered in China, even though the content had been approved by the FSB.
Lawyer Alexander Fedulov said he had attempted to contact the authorities on behalf of Mr Kolker but had been turned away from the FSB investigative department and from the prison.
He said he would file a legal complaint over the circumstances of the scientist's detention.
A number of Russian scientists have been arrested and charged with treason in recent years for allegedly passing sensitive material to foreigners.
Critics of the Kremlin say the arrests often stem from unfounded paranoia.