The duo was identified as I Gopi (30), a native of Srikakulam district, and K Jagadish (20), a resident of Vizianagaram district.
The two often visited beaches and parks in the city, and on spotting young couples, would click their pictures or shoot videos, police said.
Later, they would approach the couples and introduce themselves as policemen in plainclothes. Gopi and Jagadish would threaten to expose the couples by informing their parents or family members and demand money (Rs 500-2,000 from each of them) for deleting the videos and photos.
Meanwhile, Gopi attempted suicide in the Arilova Police Station, where he was detained last night.
The DCP said Gopi complained of stomach pain following which cops gave him a strip of ten Pantocid-L tablets. Gopi, however, consumed all the 10 tablets in an attempt to end his life and fell sick.
He was rushed to a hospital, where his condition is said to be stable.