The court ordered a seven-year prison term for JMB's explosive expert Jahidul Islam alias 'Boma Mizan', the terror outfit's Chittagong region chief Jabed Iqbal and Shahadat Ali.
Iqbal and Ali were in the dock when a Chittagong additional chief metropolitan magistrate announced the verdict on Tuesday.
Fugitive 'Boma Mizan' is one of the three top JMB terrorists, who were snatched in an ambush attack on a prison van in Mymensingh in 2014.
The court also fined the convicts Tk 5,000 each or else will have to spend another six months behind bars, Prosecutor Saifun Nahar told bdnews24.com.
On Oct 3, 2005, terrorists managed to enter the courtroom of the then additional district judge Dilzar Hossain and Metropolitan Magistrate Akram Hossain.
Court documents say they hurled a bomb, which was brought in concealed inside a book, with the two judges in the courtroom, but no-one was injured as it did not explode.
Police and lawyers managed to nab two terrorists --- Abdul Malek Laltu and Shahadat Ali. A note was found them written that it was 'a test action against judges and justice-seekers of man-made law'.