Private investigators primarily locate individuals by systematically analyzing public records, such as property deeds, voter registrations, and court documents, while utilizing specialized skip-tracing databases to track address histories.  They also conduct extensive open-source intelligence (OSINT) research, scrutinizing social media profiles and digital footprints to identify patterns in movement and associations.  When digital data is insufficient, investigators rely on fieldwork techniques, including conducting surveillance and interviewing neighbors or colleagues to verify current whereabouts.