A U.S. citizen and Boston area resident whose terrorism conviction sparked allegations of trampling free speech has been sentenced to 17-and-a-half years behind bars. Tarek Mehanna was found guilty last year of “conspiring to support” al-Qaeda and other terrorism charges. The FBI initially courted Mehanna to become an informant following his 2009 arrest, but he wound up being jailed in solitary confinement. The jury rejected the defense’s argument Mehanna was acting well within his First Amendment rights when he posted online that he supported Muslims resisting U.S. occupation. On Thursday, more than 300 supporters packed a federal courtroom in Massachusetts in support of Mehanna at his sentencing.