Omwamba was arrested earlier this month in a town near the Ethiopian border after surrendering to police.
Victims rescued from the Athi Rivers complex last September revealed they had signed contracts with an unnamed overseas employment agency, committing to pay up to $18,000 (£13,000) for visas, travel, accommodation, and other logistics, the police said.
The National Intelligence Service said that upon arrival in Russia, many Kenyans reportedly find themselves deployed to front-line combat roles after minimal military training.
Earlier this month, the government of the East African country said it would urge Russia to ban the recruitment of Kenyans to fight in Ukraine.
The Russian embassy in Nairobi has denied encouraging Kenyans to fight in Ukraine, or issuing visas “to Kenyan citizens who sought to travel to Russia with the stated pose of participating in the Special Military Operation (SMO) in Ukraine”.
The embassy added that while it does not recruit foreigners, Russian law allows foreign nationals who are legally in Russia to voluntarily enlist in their armed forces.
Ukraine’s foreign minister said on Wednesday that more than 1,700 people from 36 countries in Africa had been recruited to fight for Russia.
South Africa on Thursday said that two of its citizens had been killed in Ukraine, while another 15 had been repatriated over the past week. Two more remain in Russia getting treatment for “very severe” injuries, said Foreign Minister Ronald Lamola.
Ukrainian officials have repeatedly warned that anyone fighting for Russia will be treated as an enemy combatant, and that the only safe route out is to surrender and be treated as a prisoner of war.
However, Ukraine itself has previously come in for criticism for trying to recruit foreign nationals, including Africans, to fight on its side.