The wife of a police official known for his role in curbing Islamic extremism was shot dead in southeastern Bangladesh on Sunday, in what police suspected was the latest in a series of attacks by Islamists in the majority-Muslim nation.

Three assailants riding a motorcycle shot Mahmuda Aktar, 33, when she was on her way home after putting her son onto a school bus in the port city of Chittagong, said Humayan Kabir, additional deputy police commissioner of Chittagong.

Bangladesh secular activist killing A Bangladeshi policeman stands guard at the site of the murder of a law student, hacked to death by four assailants the night before, in Dhaka on April 7, 2016. Photo: Getty Images/MUNIR UZ ZAMAN/AFP

They shot her in the head three times, Kabir told Reuters by telephone.

There might be a militant link as her husband Babul Aktar, superintendent of police, played an important role in apprehending top militants, Kabir said.

Islamist militants in Bangladesh have carried out a series of killings since early last year, with liberal bloggers, academics and members of religious minorities among their victims.