If the murderer flees and takes refuge in India—
But India should immediately return that murderer to Bangladesh.
There will be no negotiation on justice. Giving shelter to murderers means directly aiding the crime. If India does not return the murderers - then the Indian embassy on Bangladesh soil.
Not a moment will be allowed to pass.
Bangladesh is not a safe haven for criminals.
And the brokers of crime will have no place here.

It's not a threat—
It is the thunder of the people,
It is a declaration of justice,
This is the ultimate position of sovereign Bangladesh.

return the murderer—Otherwise the question of diplomatic relations does not arise.