Partha Saha, who was arrested in Konnagar in Hooghly, was involved in digitally falsifying documents and forging identity cards in tandem with Konnagar-based police officer Bappa, said police. Bappa is still absconding.

Bappa and the dismissed constable Gopal Das are said to be the brains behind the racket. Four constables have been arrested so far following the exposure of the scam on Monday.

Jawed Shamim, DC (DD) today said that Saha’s studio had been used for morphing and superimposing photographs on the identity cards of illegally recruited candidates.

Using the tampered admit cards, the dummy candidates used to impersonate the real ones in both the physical and written exams.