The suspect 48-year-old Rasanayagam Sarvanandam had been arrested from the Wattakachchi area, according to Police Spokesman SP Ruwan Gunasekara.
He is a resident of Hudson Road in Killinochchi.
The Police Spokesman said that the arrested suspect is to be handed over to the CID who is conducting the investigation.
The investigating team including the IGP and the Senior DIG in charge of the CID had gone to the Batticaloa, Vavunathivu area for the investigations.
The two deceased constables are 35 and 28 years of age.
They are residents of Udugama, Galle and Kalmunai areas.