The accused are said to be members of Jamaatul Mujahideen Bangladesh and were found responsible by the court for planning the attack that killed at least 22 people, including 18 foreigners.
Khaleda Zia, a rival to Prime Minister Sheikh Hasina, is already behind bars after being handed a five-year term in February on separate embezzlement charges. The terms will run concurrently, meaning she will spend an extra two years in jail.
In 2013, a court had sentenced 152 soldiers to death for the 2009 killings in which dozens of officers were shot, hacked to death or burnt alive before being dumped into sewers or shallow graves.
Convictions of security force members are rare in Bangladesh. Rights activists say they frequently carry out unlawful killings and are effectively able to operate in a climate of impunity.
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