The detainee was identified as Prasad Saha, son of Surendranath Saha of Terokhada upazila in Khulna and former constable of Benapole Port Police Station.
Officer-in-charge of Benapole Police Station Mamun Khan said a sedition case has been filed against Prasad who was arrested from Mirpur area of the capital on Tuesday.
The detainee was produced before a court on Wednesday seeking 10-day remand for his interrogation. The court fixed Thursday to hear the remand prayer, the OC said.
Prasad previously worked at Benapole Immigration Check Post and was transferred to Benapole Police Station last month, he added.
According to the case statement, Prasad handed over two pen drives with confidential information to Indian police in 2018.
On October 25 last, members of Directorate General of Forces Intelligence and Rapid Action Battalion (Rab) held an army man and seized a pen drive with valuable information from a hotel at Kamalapur in Dhaka.
Later, Prasad was found involved in leaking information.