Prosecutors had previously asked for the most serious charges against the 24-year-old native of Ridgefield, Conn., to be thrown out. Those charges carried 15-year sentences.
Before the verdict was read, Tobin delivered his final statement to the court.
"Your Honor, respected participants in the trial, I consider myself not guilty. I am a student. I came here to study," he said in Russian.
Addressing an initial charge of organizing a drug den, which a prosecutor threw out earlier this week for lack of evidence, Tobin said that people would gather in his rented apartment "just to socialize."
"I don't have anything to do with drugs," he said. "I ask you to decide my case fairly. I never offered or sold anyone drugs."
What would have been a run-of-the-mill drug case was tinged with an aura of espionage after the Russian security service accused him of ties with American intelligence though he was not charged with spying.
Tobin was detained Jan. 26 as he left a nightclub in the central Russian city of Voronezh, and police say he had a matchbox containing marijuana. More of the drug was uncovered during a search of his apartment, police said.
After his trial opened this week, prosecutors said the charges of organizing a drug den and distributing narcotics as a member of an organized group could not be upheld. But they called for Tobin to be convicted for drug possession and obtaining drugs with the intent of distribution.
The accusation of intelligence connections came about a week after the United States' arrest of FBI agent Robert Philip Hanssen on charges of spying for Russia, which escalated tensions over espionage between Washington and Moscow.
Tobin, a graduate of Middlebury College, studied at a U.S. military school and at the Defense Language Institute in Monterey, Calif. He was studying political science at Voronezh State University.
Following his formal arrest on Feb. 1, Tobin has been held in a jail in Voronezh, where U.S. consular officers have occasionally been able to visit him.
Defense attorney Maxim Bayev said his client was being held in relatively good conditions, in a six-person cell with one or two other cellmates. He said that boredom was the greatest problem since Tobin's requests for a television and his own books were turned down.
For more information, read Free Jack Tobin.
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