Nazrul Islam fled Bangladesh to escape the gallows and landed in Belgium after a brief stop-over in Calcutta. But his return to the city a month ago proved to be his nemesis, as the 38-year-old and his three associates were arrested in Garia on Sunday.

Nazrul and the other three — brother Oidul, Zakir Hussain and Shahid Ahmed Manzir — have been convicted for killing leaders of Sheikh Hasina’s Awami League.

S.N. Gupta, the deputy inspector general (operations) of the CID, said the Bangla quartet have been booked under the Foreigners’ Act as they had entered the country without valid documents.

Sleuths said they had been tipped off that a Bangladeshi national who had sneaked into the state through the India-Nepal border had been hiding in the city. “We immediately activated our sources who fanned out in the fringe areas,” said Gupta.

The CID learnt that four men who spoke Bengali in Bangladeshi accent had been staying in two rented houses in Garia for the past two years. Three of them — Nazrul, Oidul and Shahid — had put up in one house, and Zakir in another house.

“We were also told that one of them, who later turned out to be Nazrul, had brought his wife and children,” said an officer of the CID’s special operations group. The police first picked up Zakir, who led the cops to the others in the gang.

“We have not arrested Nazrul’s wife and children because they came here with valid passports and visas,” said Gupta.

Elaborating on the criminal antecedents of the four, an officer said Nazrul had murdered an Awami League MP, Mohammad Asadullah, in 2004. “Oidul and Shahid were his partners in crime.”

All three jumped bail while the trial was on and fled Bangladesh. While Nazrul was awarded capital punishment, the other two were sentenced to life imprisonment.

“Zakir, who had murdered two leaders of the students’ wing of the Awami League in 2004, was sentenced to a life-term in jail. He, too, had jumped bail while the trial was on,” said a CID officer.

The police said that two months after setting up base in Garia, Nazrul left for Belgium. “The four were quite popular in the Garia neighbourhood. They used to donate to local clubs and also took part in various social welfare activities,” the officer added.

“The neighbours knew them as businessmen. Their friends in Dhaka used to send them money through hawala.”