What Does a Private Investigator Do in a Criminal Case?
In a criminal case, a private investigator develops and verifies facts for the retaining attorney or other authorized client. The investigator does not decide guilt, negotiate a plea, give legal advice, or exercise police powers. The practical role is to test assumptions, locate overlooked information, preserve time-sensitive evidence, and present findings in a form counsel can evaluate.
Florida law expressly includes investigating witness credibility and securing evidence for civil or criminal trials within the definition of private investigation. See Florida Statutes section 493.6101. The engagement should still define the case issue, authorized tasks, reporting line, deadline, and limits before fieldwork starts.
Core Tasks for Defense Counsel
- Case-file review: organize reports, recordings, photographs, discovery, and timelines to identify conflicts or unanswered factual questions.
- Witness location and interviews: find relevant people, request voluntary interviews, document what was said, and preserve accurate contact information.
- Scene and route work: document visibility, lighting, distances, access points, cameras, travel time, or changed conditions without disturbing the location.
- Record and media research: seek lawful public records, open-source material, and potentially relevant video before routine retention periods expire.
- Lead verification: corroborate alibis, identities, relationships, ownership, or chronology through independent sources.
These tasks support legal strategy, but counsel decides materiality and how a finding is used. Florida's Rules of Criminal Procedure, including rule 3.220, govern criminal discovery; a private investigator is not a substitute for that formal process.
Witness Work Requires Neutral Documentation
A good interview seeks the witness's memory, not a preferred answer. Investigators should identify themselves appropriately, avoid threats or promises, distinguish personal knowledge from hearsay, record consent where required, and document the interview setting and participants. A refusal to speak must be respected. Repeated or deceptive contact can damage a case and expose a witness to needless pressure.
Reports should separate the witness's words from the investigator's observations and later analysis. Material inconsistencies belong in the report even when they do not favor the client. Counsel can then compare the account with dispatch logs, video, physical conditions, digital records, or other testimony. Our criminal investigation services are structured around documented facts rather than a predetermined conclusion.
Evidence Preservation and Specialist Boundaries
Useful evidence is not automatically admissible evidence. Florida requires authentication or identification sufficient to support that an item is what its proponent claims. See Florida Statutes section 90.901. Investigators help by retaining original files where possible, logging source and collection time, avoiding unnecessary alteration, documenting transfers, and preserving contextual information.
Some work requires a separate expert. Device acquisition, DNA interpretation, accident reconstruction, firearms analysis, medical causation, or audio authentication should be assigned to a qualified examiner in the relevant discipline. NIST explains that forensic science includes multiple specialized fields and emphasizes method limitations, quality assurance, and validation in its forensic science overview. A PI may coordinate or document that work without overstating technical expertise.
How Attorneys Should Scope the Engagement
The strongest engagements begin early, especially when surveillance video, social posts, physical conditions, or witness memories may change. Counsel should provide the charging document or issue statement, critical dates, known witnesses, discovery status, prohibited contacts, and a prioritized question list. Updates should travel through an agreed channel, with urgent exculpatory or safety information escalated promptly.
Before hiring, verify both the investigator and agency through the Florida Department of Agriculture and Consumer Services license search. Ask how notes, recordings, original media, conflicts, subcontractors, expenses, and testimony are handled. A competent investigator will define limitations and report unfavorable facts; “guaranteed results” are a warning sign.
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