Evidence related to legal proceedings in courts, state institutions, or entities empowered to issue public authorizations is compiled by private investigators (PIS detectives). These investigators gather information pertaining to criminal activities and their culprits, supporting private prosecutions and providing crucial facts for plaintiffs involved in criminal, administrative, litigation, civil, and other legal actions.

The criminal procedure law permits the involvement of private detectives in client or prosecution investigations. This entails private investigators, upon the request of a defense attorney or a concerned party, collecting evidence essential for the party to safeguard or assert its rights during court proceedings or before other relevant institutions. In essence, private investigators work under the directive of attorneys or parties involved in legal proceedings to amass pertinent material evidence crucial for the protection or exercise of rights in the presence of courts or other entities.