Four days after cracking a Rs 80-lakh home-loan fraud at the Regent Park branch of Syndicate Bank, the Criminal Investigation Department (CID) arrested a former manager of the branch early on Tuesday.

Biswanath Das, 45, was reportedly instrumental in providing loans to the 12-member gang held responsible for the fraud. He was detained at his residence in Serampore.

?It appears that Das, who was working in the zonal office of the bank, had received money for granting the loans. He was clearly aware of what the group was up to,? said Durga Prasad Tarenia, inspector-general of police (CID).

Home loans of all the members of the gang had been sanctioned at the Regent Park branch.

The CID had arrested five people, including Trinamul Congress president of ward 100 Bibhu Nandy, in connection with the case on Friday.

The cops claimed that Nandy helped the gang members procure fake documents. The party maintained that he was framed to tarnish his image before the municipal polls. Nandy is set to take on the CPM councillor in the ward.

Nandy was granted bail on Monday. ?We are looking into how and why Nandy was granted bail,? Tarenia added.

The fraud came to light when the zonal office of the bank discovered that the dirty dozen were not paying their instalments for the past couple of months.

A probe revealed all of them had bagged the loan by providing fake documents. Soon after, a complaint was lodged with the CID without informing the branch.

The CID found out that Manik Roy, Asit Kumar Das, Swapan Roy and Dilip Majumder, along with eight others, had allegedly conspired to obtain bank loans by providing fake documents to meet their personal requirements.

Police claimed that Nandy, in addition to providing fake documents to the gang members, let them use a property he was promoting.

?For this service, he collected between Rs 40,000 and Rs 50,000 from each member,? said an officer.

Dilip Majumder, a former bank employee, reportedly co-opted Das, police said.