Science Fair Project Encyclopedia A private investigator, or PI,
is a person who undertakes investigations. They often work for
attorneys in civil cases or on behalf of a defense attorney.
Many work for insurance companies to resolve claims. Before the
advent of no-fault divorce, many private investigators were
hired to search out evidence of adultery or other illegal
conduct within marriage to establish grounds for a divorce.
Despite the lack of legal necessity for such evidence any more,
according to press reports collecting evidence of adultery or
other "bad behaviour" by spouses and partners is still one of
the most profitable activities investigators undertake. They
have also been frequently found in fiction as a stock character;
perhaps the most famous of these is the Sherlock Holmes
character created by Arthur Conan Doyle, who would refer to
himself in the jargon of his age as a "private inquiries agent."
(See Crime fiction for details.) Many jurisdictions require PIs
to be licensed, and they may or ma