Mahmuda Khanam Mitu. File photo

Detectives in Chittagong yesterday seized a black microbus and detained its driver in connection with Sunday's killing of Mahmuda Khanam Mitu, wife of Superintendent of Police Babul Akter.

They were verifying to see if the microbus was the one seen in the CCTV footage following the bike-riding assailants, Chittagong Metropolitan Police Commissioner Iqbal Bahar told The Daily Star over the phone last night.

He, however, did not give any details on where and when the vehicle was seized.

The driver was being quizzed at the Detective Branch office, said DB sources.

Police have also arrested a former Islami Chhatra Shibir activist in connection with the gruesome murder.

Chittagong police suspect that a parked black microbus might have had the backup force for the killing of Mitu.

Analysing the footage, police found that the bike-riding assailants came from the GEC intersection, stabbed and shot Mitu and fled through Golpahar area of the port city.

The black microbus was seen following the motorbike when the assailants left the scene.

Talking to the media, Chittagong Metropolitan Police Commissioner Iqbal Bahar said it appeared that the microbus was used as a backup force.

“We identified some spots where the microbus stopped … , ” said CMP Additional Commissioner (crime and operation) Devdas Bhattacharya.

During investigation, police learnt that the stolen motorcycle used in the attack belonged to a cook from Boalkhali. It was reported stolen from his home on May 8.

Police have recovered the bike.

On the fateful Sunday morning, Mitu reportedly received a text that said there would be an assembly at her son's school and her son should be there half an hour before the usual time.

The school authorities denied sending any text. Police suspect the assailants had sent the SMS to trick her, said a family member.

However, police are yet to be sure if such a text was sent to Mitu's phone as the assailants took her phone.

Investigators seeking anonymity said the attack on Mitu bore the telltale signs of a militant attack. The findings suggested that it was well planned and was carried out in a well-organised manner, which militants had not done in their previous attacks, they claimed.

The CMP commissioner last night said they were investigating with all aspects in mind.

Admitting that the killing was well-planned, he said it was also true that the criminals might have had left some clue no matter how well planned the murder was. "There are obviously some mistakes and we are working with those," he told The Daily Star.

Investigators are having trouble identifying the bike-riding assailants as the picture of the CCTV footage was blurry.

Another camera installed at the adjacent Kalimandir (temple) was inactive on that morning. If the camera was active, the faces would have been clear, said a police official.

The CMP commissioner said they would investigate whether the camera of the temple was off due to technical problems or other reasons.

“We do not know why nothing was recorded … We do not know whether there is any technical problem or other reasons,” said Michael Dey, secretary of the temple.

On the day of the incident, police went to the temple after 8:00am. Examining the CCTV memory card, they found that there was no video stored, he said, adding that they have no permanent staff to run the cameras.

Apart from ''militants' link'', police are now focusing on possible involvement of Islami Chhatra Shibir and other connections in the killing, he added.

EX-SHIBIR MAN ARRESTED

Police yesterday detained an ex-activist of Islami Chhatra Shibir suspecting his link with the murder.

Tipped off, police detained Abu Naser Binnu, aged about 40, in Farhadabad area of Hathazari in Chittagong yesterday, said CMP's Additional Commissioner Bhattacharya.

He was involved in politics of Shibir since 1995 but had left for a middle eastern country, said the CMP official at a press conference held at its headquarters.

He claimed that Nasr, to hide his other activities, was working as a caretaker of a local mazar.