While monitoring the usual channels, Indian police stumbled upon a detailed plot for what would become the bloodiest Islamic State group-linked attack in South Asia.

The father of two of the suspected Easter suicide bombers was arrested on suspicion of aiding his sons on Thursday, according to Sri Lanka's former navy chief, as investigators continued to comb his Colombo mansion for evidence of the attacks that killed 359 people.

Jacinda Ardern's office issued a statement responding to the Christchurch claim that described Sri Lanka’s investigation as “in its early stages.”