Sagar Ali, who was arrested in connection with the murders of three members of a family in Savar's Ashulia two months ago, was plotting to kill a public representative in Tangail as well, according to the Rapid Action Battalion.
The authorities are scrutinising the information Sagar gave them during questioning, RAB spokesperson Commander Khandaker Al Moin said at a media briefing in Dhaka on Friday.
On Sept 30, police recovered the mutilated bodies of a couple and their child from a flat in Ashulia's Jamgra area.
The RAB subsequently arrested Sagar and his wife, Ishita Begum, from Gazipur's Shafipur on Oct 2.
Later, the RAB said Sagar went to the house of Moktar Hossain alias Babul and Shahida Begum, both apparel factory workers, on the pretext of providing herbal treatment.
His motive was to make them unconscious by administering sleeping pills and loot their belongings. Unsatisfied with the money he found there, he slit the throats of Moktar, Shahida and their 12-year-old son.
Sagar had previously killed four other members of the same family earlier in 2018. He was out on bail when he committed the latest murders, Moin said.
A political leader from Tangail had arranged for Sagar's bail. In return, he was given the task of 'murdering' a local representative, Sagar told the RAB during interrogation.
“During the initial interrogation, Sagar has revealed many things. While he was in jail, an influential figure from his locality helped him secure bail. He then paid Sagar to kill another representative."
“These were Sagar's words. Many outlets have published reports on it and the media is conducting its own investigation. We are scrutinising the information given to us by Sagar to identify the political leader involved in the murder plot."