A senior police officer said Nabin Mondal was arrested from neighbouring Purnia by a Bengal Police team who were assisted by their Bihar counterparts.
With this, three persons have been put behind the bars in connection with the gangrape last week.
The 30-year old woman, a mother of three children, was allegedly raped on the night of April 1 by 21-year old Mondal, who barged into her home in the absence of her husband.
Unable to bear the humiliation, the 30-year old set herself on fire on Wednesday last and died at the Malda Medical College the next day.
The incident comes nearly two months after a 20-year-old tribal woman was allegedly gangraped at the instructions of a Kangaroo court in Birbhum district which sparked an outrage across the country.
The Calcutta High Court on Friday took suo motu cognisance of the incident and directed the district administration to submit a report.