Police informants in California provide the authorities with information that leads to search warrants, wiretaps, surveillance and the solving of crimes. The types of informants can range from random citizens who are aware of criminal activity...to agents of the police who infiltrate criminal organizations and report on their activities.
No doubt informants are a very useful and effective law enforcement tool. But when their purported information leads to search warrants and wiretaps, the privacy of the suspects gets invaded. To insure that this invasion of privacy is warranted, the law requires that standards of reliability be observed.
For example, the judge issuing the search warrant can question the informant...either through live testimony or written affidavits. Specifically, the judge looks to see whether (1) the informer has a history of providing tips that proved reliable, or (2) there is independent corroboration of the informer's story.