ST. PETERSBURG — For two weeks, as his brother stood trial on terrorism-related charges, Avni Osmakac watched in silence. But days after the jury delivered a guilty verdict that could put his brother in prison for life, Osmakac is speaking out about what he says are the FBI's unfair tactics.

From his family's small bakery and grocery store in St. Petersburg, Osmakac said Thursday that his younger brother Sami was "brainwashed" by undercover FBI agents and an informer who received money from the government for his role. Before he met an odd cast of characters and became estranged from his family, Sami Osmakac was a lost and isolated young man who had only a vague interest in Islam, his brother said. By the time of Sami's arrest in 2012, he was spouting extremist rhetoric and purchasing weapons from an undercover agent.

"Everything my brother said on these videotapes, that's not my brother, that's a creature made by the government," said Avni Osmakac, 30.

The brother he knew was a shy young man who dropped out of high school, got his diploma through the GED test, and worked in the family's bakery. The Osmakac brothers weren't big drinkers, Avni said, but they enjoyed the South Tampa club scene and often spent nights at MacDinton's, the Irish pub on S Howard Avenue that Sami later planned to bomb. Immigrants from Kosovo, they are Albanian Muslims by heritage, Avni said, though they are secular in practice. He and Sami became U.S. citizens.

Avni Osmakac said he and his brother were so close they would have died for each other. But that changed in 2009, after the family traveled to Kosovo to attend another sibling's wedding. On the way home, their plane suddenly began to drop, the lights went off, and oxygen masks fell. It was the first time Avni saw his brother pray. In the weeks and months that followed, he noticed Sami was behaving strangely. He came downstairs one morning to find Sami staring at a turned-off television set.

"What are you doing?" he asked. "Watching TV," Sami replied.

The family urged Sami to see a doctor, but he refused, saying the doctor would only try to kill him. Avni said his family has a history of mental illness, which has affected a few of his siblings and grandparents on both his mother and father's sides.

Sami stopped talking to his parents and brother, Avni said. Though he still lived at home, he began spending all of his time with a man named Russell Dennison, whom he met at a mosque. Avni said it was Dennison, an American convert to Islam, who planted extremist ideas in his brother's head. The pair began filming videos together in which they criticized nonbelievers.

"This guy Dennison is an undercover agent," Avni claimed on Thursday. "I tried to tell (Sami) to stay away, but he wouldn't listen to me."

In a 2012 interview with the Tampa Bay Times after Osmakac's arrest, Dennison rejected his past association with the Kosovo-born man. "My government has done the right thing," he said then.

On Thursday, an FBI spokesman would not comment on Dennison's background or his ties to the Osmakac case.

Dennison's father, a florist in Pinellas Park, said his son was not involved and had left the United States several years ago to work in the Middle East.

"Honey, I wish my son were an FBI agent," Russell Dennison Sr. said. "That would be a new one. That wouldn't be a bad job."

Osmakac's attorney George Tragos also would not comment on whether Dennison was an undercover agent. He is working on an appeal.

What is clear is that the FBI was listening to Dennison and Sami Osmakac's phone conversations in 2010. Recordings of several of the calls were played during the trial, including one in which the men discussed articles they'd read in Inspire, the English-language magazine distributed by al-Qaida. Asked during the trial how Dennison and Osmakac knew each other, federal prosecutors refused to discuss their relationship.

Two years after his brother was arrested for plotting to bomb several locations in Tampa, Avni Osmakac said the case has taken a heavy toll on his family. Customers who learned of Sami's arrest stopped coming to the bakery and the family encountered a series of unscrupulous attorneys, Avni said, before meeting Tragos. The Osmakacs sold their home to cover Sami's legal fees and are now renting an apartment, he said.

"The real terrorism is the government against Muslims right now," Avni said. "They're looking for people, young, that have no idea about religion and are isolated. In every case I've been reading about, it's the same thing."

Anna M. Phillips can be reached at aphillips@tampabay.com or (813) 226-3354.