Arthashastra
तस्माद् बाह्यम् अधिष्ठानं कृत्वा कार्ये चतुर्विधे । शौच अशौचम् अमात्यानां राजा मार्गेत सत्त्रिभिः ॥
Hence having set up an external object as the butt for all the four kinds of allurements, the king shall, through the agency of spies (satri), find out the pure or impure character of his ministers (amátya).
english translation
tasmAd bAhyam adhiSThAnaM kRtvA kArye caturvidhe । zauca azaucam amAtyAnAM rAjA mArgeta sattribhiH ॥
hk transliteration by Sanscript