When his son was sent to fight in Ukraine, Sergei begged him not to go.
"You've got relatives there. Just refuse," Sergei recalls telling Stas, who was already an army officer. "But he said he was going. He believed it was right. I told him that he was a zombie. And that, unfortunately, life would prove that."
Sergei and Stas are not the real names of this father and son. We've changed them to protect their identities. Sergei has invited us to his home to tell us their story.
"So off he went to Ukraine. Then I started getting messages from him asking what would happen if he refused to fight."
Stas told his father about one particular battle.
"He said the [Russian] soldiers had been given no cover; there was no intelligence gathering; no preparation. They'd been ordered to advance, but no one knew what lay ahead.
"But refusing to fight was a difficult decision for him to take. I told him: 'Better to take it. This is not our war. It's not a war of liberation.' He said he would put his refusal in writing. He and several others who'd decided to refuse had their guns taken off them and were put under armed guard."
Sergei made several trips to the front line to try to secure his son's release. He bombarded military officials, prosecutors and investigators with appeals for help.
Eventually his efforts paid off. Stas was sent back to Russia. He revealed to his father what had happened to him in detention: how a "different group" of Russian soldiers had tried to force him to fight.