BOSTON — A man who grew up in the Boston suburbs was convicted Tuesday of conspiring to help al-Qaida and plotting to kill U.S. soldiers in Iraq after a two-month trial in which jurors heard references to Osama bin Laden and saw dramatic images from the Sept. 11 attacks.

The federal jury deliberated about 10 hours over three days before finding Tarek Mehanna, 29, guilty of four terror-related charges and three charges of lying to authorities. He faces life in prison, though his attorneys plan to appeal.

“The heart of the case is really this: Did Mr. Mehanna conspire to support terrorists, conspire to kill in a foreign country and then did he lie to federal investigators?” said Massachusetts U.S. Attorney Carmen Ortiz. “Today a jury of his peers concluded that he did that.”

Ortiz said the references to bin Laden and 9/11 were relevant and not inflammatory, but defense attorneys said they made it impossible for their client to get a fair trial.

“This is one the most cynical government cases I’ve ever seen tried,” said defense attorney Janice Bassil. “Picture after picture just wanting to scare the jury. Deal after deal to government witnesses. All those government witnesses did way more than Tarek Mehanna.”

Prosecutors said Mehanna and two friends conspired to travel to Yemen so they could receive training at a terrorism camp and eventually go to Iraq to fight and kill U.S. soldiers there.

When the men were unable to find such a training camp, Mehanna returned home and began to see himself as part of the al-Qaida “media wing,” translating materials promoting violent jihad and distributing them over the Internet, prosecutors said.

One of the men, Kareem Abu-zahra, testified under a grant of immunity. A third man, Ahmad Abousamra, was also charged. Prosecutors say they believe Abousamra is in Syria.

Mehanna, who was born in the U.S. and raised in the Boston suburbs, will be sentenced April 12. His mother, Souad Mehanna, sobbed after the verdict was read. Mehanna’s lawyers also wept.

Mehanna’s father, Ahmed, a professor at the Massachusetts College of Pharmacy and Health Sciences, said he was stunned by the verdict.

“I can’t even think,” he said. “It was political.”

Andrew March, a Yale University professor who testified for the defense as an expert witness, said the verdict sends the message to Muslim Americans that they do not have free speech.

“I do what he did almost every single day at Yale University. I teach Islamic law, I study Islamic law. I translate things about al-Qaida. I teach people to debate,” March said. “Because I’m not a Muslim and because of what my name is, I have no problem doing it.”

During the trial, Mehanna’s attorneys portrayed him as an aspiring scholar of Islam who traveled to Yemen to look for religious schools, not to get terrorist training. They said his translation of controversial publications was protected by the First Amendment.

Prosecutors focused on hundreds of online chats on Mehanna’s computer in which they said he and his friends talked about their desire to participate in jihad, or holy war.

His lawyers acknowledged that Mehanna expressed admiration for Osama bin Laden but said he disagreed with bin Laden and other al-Qaida leaders about many things, including the use of suicide bombers and the killing of civilians.