Police claimed that they are still looking for their informant Kamrul Islam Sikdar Musa in connection with the Mitu killing case, but Musa's wife said the law enforcers had already picked him up over a week ago.

Motaleb Mia Wasim, an accused in the case, reportedly told a magistrate on June 26 that Musa hired seven to eight hit men, including him, for killing Mahmuda Khanam Mitu, the wife of Superintendent of Police Babul Akter.

Now, only Musa's arrest could unveil the mastermind of the brutal killing and whether Babul had any hand in the murder of his wife, police sources said.

Babul had been picked up early Saturday from his father-in-law's home in the capital and was interrogated for 15 hours by three officers of the rank of deputy inspector general, police and family sources said.

During interrogation he was reportedly given two options; Face trial for his alleged link in the murder or resign.

He signed his resignation letter but it is yet to be submitted to the police headquarters, the sources added.

Musa's wife Panna Akter yesterday went to Rangunia Police Station to file a general diary about her “missing” husband, but the police officer on duty there advised her to go to another police station.

Panna told The Daily Star over the phone that after staying a couple of weeks at her father's home in Rangunia, she returned home in the port city's Kala Mia Bazar area on June 21. Some neighbours then told her about police officials visiting her home.

She said she then called her husband over the phone and after consulting with him, she along with her two sons and a brother-in-law went to the home of her husband's friend Nur Nabi in Kathgar area.

“On that night my husband called Nabi over the phone and then told me on his phone that he would visit me a day later,” she said.

The following morning, a group of plainclothes policemen went to the house and asked Nabi and Panna to call Musa over the phone and ask him to come over, she claimed.

“They asked us to talk to Musa in such a manner that he did not suspect that policemen were with us,” said Panna.

When Nabi called Musa, Musa told him that he was near his house and at that moment the “policemen instructed other law enforcers” outside to arrest Musa, she claimed.

When asked, Panna said her husband went to Anwara on June 4 and returned home the following morning, the day Mitu was killed.

She claimed Musa was not involved in the killing. “My husband is a sand trader who also sells bricks,” said Panna, adding that her husband had no case filed against him earlier.

But she could not give any details about his work as an informant.

Investigation officer of the case Md Kamruzzman, assistant commissioner of CMP Detective Branch, refuted Panna's allegations that police had arrested Musa.

“They can make any claim they want but actually they are not telling the truth. May be [they are saying this] to save the criminals … ,” said the IO.

Additional Commissioner (Operation and Crime) Devdas Bhattacharya said they are still looking for five people, including Musa, in connection with the murder.

Police are going to produce one of the two suspects they arrested before a court for recording his confessional statement, said sources in the CMP. The two suspects -- Anwar and Wasim -- had made contradictory statements about the killing.

In his statement, Anwar said Wasim shot Mitu while Wasim said he fired shots in the air and that Mitu was killed by Musa's bullet.

Wasim has eight other cases filed against him, including one for murder,  said a CMP official. During police interrogation Wasim admitted that he killed Mitu but before the court he switched his story, the official said.

Two eyewitnesses would be taken to court for recording their statements, which would help verify their claims, the official added.

One of the witnesses is the driver of a microbus while the other is a staff of a nearby hotel.