The arrest was made on August 13, a press release issued by R K Tutusana, PRO police today said.
The arrested PLA member was identified as Gurumayum Khugamani Sharma alias Nanao (27) of Wangkhei Pukhrabam Leikai, the release said adding that he was involved in serving demand letters to various government offices, general public and businessmen.
Some incriminating documents were also seized from the posession of the arrested militant. A case has been registered at Porompat police station, in Manipur's Imphal East district and investigation is on, the release added.