Prosecutors were asking for a nine-year jail sentence to the 82-year-old man, who was excused from attending the court’s final hearing due to health reasons.
The verdict can be appealed against.
Earlier in court, Manovas claimed he was collecting information for his Ukrainian friends who had infiltrated Russia’s special services and were acting in the interests of their homeland.
"I am not guilty, please let me go," Manovas said in his last word to the court in March.
From 2018, he had allegedly been collecting information about political parties, state institutions, and the economic life of the country, according to law enforcement. There is no evidence that he could have gathered and used classified information.
The Russian GRU and Manovas had agreed to cooperate before 2018, law enforcement data show.
The State Security Department (VSD) earlier said the suspect had been paid for spying.