One month into the recovery of the body of ASP Mizanur Rahman of Highway Police from Birulia Bridge area in Savar, the law enforcement agency has finally been able to unearth the mystery behind the killing.Police said the senior official of the Highway Police was killed by muggers inside their vehicle after they recognized Mizanur as a cop.“We have arrested Shah Alam alias Budda, an active member of the mugger gang who was inside the car during the crime, on July 22. He confessed that they were waiting in Sector-3 in Uttara on June 21 to rob their potential target. When plain clothed Mizanur came, they made him to board their vehicle posing as passengers,” additional police commissioner and chief of Counter Terrorism and Transnational Crime (CTTC) unit Monirul Islam said.After taking Mizanur into their car, driver Zakir put music on high volume, switched of all the lights and started driving rough through allies in Uttara, reports BSS.“When they realized that Mizanur was a senior cop, one Mintu, who was sitting on the back seat, hit him hard on his head. Other muggers Kamal and Faruk strangled Mizanur with a piece of cloth and make sure his death. They later dumped his body in a bush beside Birulia Bridge,” Monirul added.The CTTC boss said there were four muggers inside that vehicle and police are now trying to detain the remaining three.