India, Dec. 23 -- Bangladesh's unrest has started spilling across borders, with the country suspending visa services for an indefinite period on Monday after a small group of protesters gathered near its high commission in New Delhi. India too has summoned Bangladesh's envoy and conveyed strong objections over attacks on minorities and diplomatic missions.

The fallout has also been visible on the streets of Kolkata, where large protests erupted outside the Bangladesh High Commission, fuelled by outrage over the lynching and burning of a Hindu man in Mymensingh and fears of growing Islamist mob violence next door.

At the heart of the turmoil lies a grim chain of events: the brutal mob killing of a Hindu garment worker on unproven blasphe...