He was detained from Dhaka's Shyamoli at 9:30pm on Sunday, Sirajganj district Superintendent of Police Mirazuddin Ahmed told bdnews24.com.
Dhaka Metropolitan Police Deputy Commissioner Masudur Rahman said Miru was being taken to Sirajganj after the district's detective police arrested him with the help of sleuths in Dhaka.
Earlier in the day, Shahzadpur Upazila unit of the ruling Awami League recommended his expulsion as the party's Sirajganj district unit organising secretary.
Police said Miru opened fire when rivals surrounded his house during clashes between his supporters and those of sacked Shahzadpur Awami League president Abdur Rahim (VP Rahim) last Thursday.
Mayor Miru has also admitted to opening fire. But he claimed he fired a shot in the air in retaliation to shots fired by his rivals.
Police, however, said only Miru's gun was fired during the clashes.
The clashes erupted following the beating of Rahim's brother-in-law Bijoy Mahmud, a local leader of Bangladesh Chhatra League.
Shimul's wife has started a case naming Miru, his brother Habibul Haque Mintu, and 16 others over the killing of her husband.
Besides Miru, police have arrested Mintu and local Awami League leader KM Nasiruddin.
Shahzadpur Awami League has also recommended expulsion of Nasiruddin.
Miru's another brother Hafizul Haque Pintu was earlier arrested in a case over the beating of Bijoy.
A total of eight persons have so far been arrested in the two cases.