A former activist of the Parbatya Chattogram Jana Sanghati Samiti (PCJSS) was shot dead in Bandarban on Saturday.
A group of armed men shot Anumang Marma, 45, in Rowangchhari upazila and fled the scene along with the body, said police.
The group also abducted two locals at the time, whom the army and police are now trying to rescue.
Rowangchhari police station OC Abdul Mannan said they had yet to identify the persons or the group involved in the incident.
Armed conflict is not uncommon in the Chittagong Hill Tracts.
On February 2, a Bangladesh Army trooper and three others, described as activists of the PCJSS, died in a gunfight in Bandarban.
The PCJSS was formed in 1972. But a group of indigenous people, led by Prasit Bikash Khisa, formed the United People's Democratic Front (UPDF) 16 years later, opposing the peace treaty.
The PCJSS had inked the peace deal on December 2, 1997, with then-Awami League government, led by Sheikh Hasina, ending over two decades of tribal insurgency and bloodshed in the hill districts.
In 2010, the PCJSS saw another faction, PCJSS (MN Larma), break away. The main PCJSS is currently led by Jyotirindra Bodhipriya Larma, also known as Santu Larma.
All the regional parties reached a compromise in 2015 and the violence almost came to an end.
But when a group split from UPDF in November 2017, calling itself UPDF (Democratic) and led by former UPDF leader Tapan Jyoti Chakma, the hills started to become violent again.
