Three other Election Commission officials were arrested in the case earlier
The Counter-Terrorism and Transnational Crime (CTTC) unit arrested another Election Commission staff from Chattogram in connection with providing National Identity Card (NID) to Rohingyas on Thursday night.
The arrestee is Md Mostafa Faruk, hailing from Feni.
He was working as a data entry operator under a project in the Chattogram election office for updating voter list.
Earlier, three Election Commission officials were arrested in the case including office assistant Joynal Abedin, driver Bijoy Das and his sister Sima Das.
The Counter-Terrorism and Transnational Crime Unit is investigating the case lodged over NID forgery for Rohingyas in Chattogram.
"We recovered important documents along with a list of Rohingyas from his possession during an interrogation. Later he was arrested on Thursday night," said Mohammad Shaidullah, deputy police commissioner of CTTC at Chattogram Metropolitan Police, in a press briefing on Friday morning.
Police seized two laptops, two pen drives, one internet modem, two signature pads from his possession.
Mostofa worked at the EC under a project from 2014-2016.
He joined again under a new project as a technical expert later in 2016.