A Bahraini man died this week from tear gas inhaled during security operations in a Shi'ite Muslim village, rights activists said on Tuesday, and the government said some police were under investigation for "exceeding their authority".
Small scale protests and clashes with security forces take place on an almost daily basis in areas where the majority Shi'ite population live after the Sunni-dominated government crushed a pro-democracy movement earlier this year.
Nabeel Rajab, head of the Bahrain Centre for Human Rights, said Isa al-Taweel, 60, died on Sunday after two weeks in hospital from the effects of tear gas fired by security forces in the town of Sitra. He told Reuters that Taweel, who was buried on Monday, had been inside his home at the time.
An Interior Ministry spokesman was not available for comment.
Around 30 people were killed during the protests and ensuing crackdown, including four policeman and four detainees who were in police custody.
Saudi and United Arab Emirates troops helped Bahrain stamp out protests it says were driven by Shi'ite sectarian motivations and instigated with non-Arab Shi'ite power Iran. Opposition groups deny this.
A commission of international experts has been tasked by the government to investigate the violence and charges of rights abuses during over two months of martial law that ended in May.
The government says torture is not systematic and action will be taken against anyone guilty of abuses.
An Interior Ministry statement carried by the official BNA news agency on Tuesday said some policemen were under investigation for what appeared to be potential rights abuses.
"An officer and a number of general security personnel at Budaya police station have been transferred for questioning for going beyond the authority granted them by the law," it said. "Security forces adhere to the law and abide by human rights and good behaviour with all citizens."
Rajab said the announcement arose out of a visit by the rights commission to Budaya police station earlier this week where teenagers were being held in detention.
"It's not that the government changed its attitude, it's that they were caught red-handed," he said. The commission is due to present its findings to King Hamad in October.