A Bahraini court jailed four Shiites for life Thursday over the death of an Asian resident in one of five bombings year before last, a judiciary source said.
Another Asian was killed and one wounded in the other blasts, which rocked the Manama districts of Gudaibiya and Adliya on November 5, 2012 in a kingdom hit by a Shiite-led uprising.
The victims' nationalities have not been disclosed.
It was unclear if the defendants were linked to the other bombings or if others were thought to be responsible.
They were charged with "forming and joining a terror group, premeditated murder, carrying out a bombing aimed at spreading terror, as well as using and possessing explosives to carry out a terror act," the source said.
Bahrain's main Shiite opposition bloc Al-Wefaq had condemned the attacks, insisting on its calls for peaceful protests.
Scores of Shiites were rounded up following a crackdown on protesters against the ruling Sunni dynasty in March 2011, and many have been tried and jailed.
Authorities in the kingdom, home to the US Fifth Fleet, have increased penalties for those convicted of violence, introducing the death penalty or life sentences for certain cases.
Last month, Human Rights Watch criticised "failures" in Bahrain's justice system, saying it severely punishes pro-reform protesters while offering impunity to abusive security personnel.
The International Federation for Human Rights says at least 89 people have been killed in Bahrain since the uprising began in February 2011.