Joint forces Saturday tightened security and launched a string of raids in three districts, a day after the killing of a policeman and looting of firearms by outlawed operatives in Bagmara upazila of Rajshahi, reports bdnews24.com.

Inspector general of police Noor Mohammad visited the scene of the murder in Taherpur area Saturday.

Superintendent of police for Rajshahi Didar Ahmed told bdnews24.com that security was tight.

Joint forces tightened security in Rajshahi, Natore and Naogaon and conducted house-to-house raids in different areas. The police arrested six people with suspected ties to the killing.