A former "Red Partisan" leader during World War II, Kononovs was charged in connection with the wartime raid on the village of Mazie Bati that left nine dead, including a blacksmith that Kononovs had personally shot.
Kononovs is the third Soviet-era war criminal convicted in Latvia, where the authorities are presently investigating as many as a dozen other cases.
His attorney argued Kononovs was too old to stand trial, that he could not get a fair trial in a Latvian court and that, ultimately, he simply obeyed orders in the fight against the German occupation of Latvia.
Soviet miltary leaders called Kononovs a hero for the attack and awarded him medals.
Protestors carrying signs in Russian picketed the court and a handful of foreign embassies in recent weeks.
As Kononovs entered the court room last Friday for the verdict, protestors reportedly shouted "Down with Facism" and "Death to the Court."
Human rights activist Nils Muiznieks says war crimes abuses have to be tried now while the perpetrators are still alive.
"It's important to take this step before the memory of them fades completely," he said.
But the Russian Foreign Ministry, as expected, lashed out at Latvia for Kononov's conviction, calling it a "cynical scoffing at the memory of millions of Nazi victims," according to the Russian news agency ITAR-TASS.
"An anti-Facist fighter has been convicted, and the trial creates a dangerous precedent that could grow into a massive witch hunt," the Ministry continued.
Latvia is fast becoming the former Soviet Union's most vigilant war crimes hunter.
A Latvian court last year sentenced former Soviet security policeman Mikhails Farbtuhs, 83, to seven years in prison after he was found guilty for the deaths of 31 people — members of the intelligentsia, the Latvian national militia, and others whom he helped deport to Siberia and who later died in transit, in labor camps or were murdered.
Former security police head Alfons Noviks, who directed the second wave of deportations here in 1949, died in March 1996 while serving a life sentence.
None of the alleged war criminals expected to stand trial are linked with Nazi atrocities wrought in Latvia during the German occupation, a fact of tedious and often quiet debate among Latvians but fodder for diplomatic hazing by the Russian government.
The Russian Foreign Ministry asked this week what many have been wondering since the vigilant hunt for Soviet war criminals began — what about the Nazi war criminals?
"This obviously political trial is a profanation with the backdrop of Latvia's passivity towards collaborators who are linked to Nazi war crimes," the Russian Ministry of Foreign Affairs told the Russian news agency ITAR-TASS.
Latvia has been the center of international attention in recent weeks as the case of Konrads Kalejs, wanted for the alleged murder of thousands of Latvian Jews as a member of the Nazi-backed Arajs Commandos from 1941-1944, has presented the country with a world stage on which to act.
Muiznieks thinks it should.
"I would like to see Latvian authorities pursue war criminals with a tainted past from the Nazi occupation the same as they do Soviet war criminals," he said.
Unlike those charged and convicted for Soviet war crimes, Kalejs, who denies the charges against him, is Latvian.
He is currently in residing in Australia.
Under pressure from foreign governments and Nazi hunting organizations, the Latvian government has said it will prosecute him if it gathers enough evidence.
Muiznieks and others point to Latvia's historical role as a victim in European geo-politics to explain the seeming reluctance to prosecute Latvians for war crimes.
But the Kalejs case and the prosecution of Soviet war criminals has begun a dialogue long reserved in Latvia for quiet corners.
"People here are slowly begining to talk about these things," said Muiznieks.