कौटिल्य - राजधर्म

प्रजा संरक्षणं धर्मो धार्मिकस्य महीभृतः ।
तस्मादसाधून् धर्माय निघ्नन् दोषैर्न लिप्यते ॥

- कौटिल्य

Protection of his subjects is the utmost duty of a King. In the process he has to punish/kill the rogues who trouble the subjects. There is no sin attached to such acts.

- Kautilya