INFORMER (informator) in Law, a person who informs against, or prosecutes in any of the king's courts, those that offend against any law or penal statute.
Informers were very common both in Greece and in Rome. Every corner of the streets was infested with persons who made it their constant business to pick up stories, and catch at every occasion to accuse persons of credit and reputation. These persons were called by the Greeks Συκοφάνται; for a more particular account of whom see SYCOPHANT.
Amongst the Romans, informers were of two sorts, mandatores and delatores. These played into each other's hands; the former marking down such persons as they pretended to have found guilty of any misdemeanour, and
Infrac- the latter prosecuting them. What tended to increase the
house. number of these pestilent wretches was, that the informers
were entitled to a fourth part of the effects of the person
convicted. Wicked princes rewarded and countenanced
this mischievous tribe; but Titus set on foot a most dili-
gent search after them, and punished such as he found with
death or banishment. Trajan also is praised by Pliny for
pursuing similar conduct.