The US Supreme Court
declined Monday to hear an appeal from Tarek Mehanna, the Sudbury man convicted in 2011 of federal terrorism-
The decision against Mehanna — who was convicted in federal court in Boston of conspiring to provide material support to terrorists, conspiring to kill in a foreign country, and of lying to authorities in a terrorism investigation — was hailed by law enforcement officials but condemned by his father.
Mehanna, now 31, is serving a 17½-year sentence in a federal prison in Illinois.
"I'm disappointed to see even the highest court still submissive to the executive branch's fabrication of charges," Mehanna's father, Ahmed Mehanna, 64, said in a phone interview.
"So that's my view. What do you expect me to say? It's clearly the First Amendment [at issue], and they refused to even look at it."
But US Attorney Carmen M. Ortiz, whose office prosecuted Mehanna, said in a statement that justice was served by the high court's denial.
"As evidenced at trial, Mr. Mehanna radicalized to think violence was an acceptable response to his grievances, and then he acted, first, by exploring how he and others could participate in that violence, ultimately choosing to go overseas to do so, and then by using the Internet to encourage others to support terrorism," Ortiz said.
Prosecutors said Mehanna traveled with an associate, Ahmad Abousamra, to Yemen in 2004 to join a terrorist training camp and to ultimately attack American soldiers in Iraq, but the plan failed.
Abousamra, who grew up in Stoughton, was also charged and remains at large.
When Mehanna returned home, prosecutors said, he began translating Arab-language materials into English and posting them online to promote Al Qaeda's ideology and inspire others to violent jihad.
Lawyers for Mehanna, who has said he was threatened with prosecution after refusing to serve as an informant, argued at trial that he traveled to Yemen to pursue religious studies and that his translations were protected under the First Amendment.
A lower Appellate Court upheld Mehanna's conviction last year. "We are disappointed that the Supreme Court declined to hear the case," a lawyer for Mehanna, P. Sabin Willett, said in an e-mail.
Abousamra recently made headlines when ABC News reported that officials believe he may be using his computer skills to support ISIS, or the Islamic State in Iraq and Syria, the terrorist group that is trying to establish an Islamic caliphate and has claimed responsibility for the beheadings in recent weeks of two American journalists.
On Monday, Mehanna's father said his family did not have "one iota of hope" that his son would get a hearing before the high court, in light of the news reports on ISIS.
"Unfortunately, the Supreme Court is affected by such a saga and such media frenzy," Ahmed Mehanna said. "It is a very, very sad day."
Vincent Lisi, the FBI special agent in charge in Boston, said in a statement Monday that the case against Mehanna was always strong. "From his travel to Yemen to receive training to kill American soldiers to his material support for terrorism at home, it was clear Mr. Mehanna trained to be a terrorist," Lisi said.
Martin Finucane and Milton J. Valencia of the Globe staff contributed to this report. Travis Andersen can be reached at email@example.com or on Twitter @TAGlobe.