A famous Russian scientist with cancer died two days after he was arrested and pulled from his hospital bed on charges of espionage, his family announced, Sunday.

Dmitry Kolker, 54, died at dawn on Saturday in a Moscow hospital where he was transferred from a prison in the capital, referring to a message from the authorities published by his son, Maxim Kolker, on the social network VKontakte.

Two days earlier, a court in Novosibirsk, a large city in Siberia, indicated that Dmitriy Kolker had been arrested and detained for two months.

According to this source, he was charged with “treason of the state” and “espionage” for a “foreign country”, a crime punishable by 20 years in prison.

His family says that FSB agents arrested him in a clinic in Novosibirsk, where he was being treated for cancer, and then transferred to Moscow, despite his health.

“The FSB killed my father, they knew what was in it, but they took him out of the hospital. Thank you, my country! Maxim Kolker wrote on VKontakte on Sunday, his family did not have permission to say goodbye.

Laser specialist Dmitry Kolker, PhD in physics and mathematics, ran a lab on “quantum and optical technologies,” according to the Novosibirsk State University website.

According to his son, he was suspected of spying after giving lessons at an international conference in China. During this conference, according to his son, Dmitry Kolker was constantly accompanied by an FSB agent to avoid any publication of sensitive information.

In Russia, scientists are regularly accused of espionage and convicted on sometimes controversial issues.