Truth Verified—Professional Polygraph Examinations You Can Trust

Polygraph Examinations | Sacramento & Northern California | Bonnington PI
When the truth is in question and clarity matters most, a polygraph examination can provide powerful insight and peace of mind. Whether you're navigating a legal dispute, facing accusations, or seeking closure in a personal matter, Bonnington PI offers professional lie detector testing services that are discreet, accurate, and court-ready.


Located in Sacramento, CA
Call (916) 936-7773 for a Free Consultation
Serving Folsom, Elk Grove, Roseville, the San Francisco Bay Area, and all of Northern California

What Is a Polygraph Test?

A polygraph, commonly known as a lie detector test, measures physiological responses to questions in real-time, including:

  • Heart rate
  • Blood pressure
  • Respiration
  • Skin conductivity (sweat gland activity)


These measurements help identify deceptive responses by comparing baseline reactions to control and relevant questions.

At Bonnington PI, our tests are conducted by licensed and trained examiners using validated, court-approved methods and industry-standard equipment.

When Should You Consider a Polygraph Examination?

Our clients request polygraph exams in cases involving:

Legal Investigations

  • To support or challenge claims in criminal or civil cases
  • As part of defense strategies or pre-litigation discovery
  • To establish trust in disputed narratives

Relationship & Infidelity Issues

  • To resolve questions of cheating or dishonesty
  • Used alongside infidelity investigations for complete clarity

Workplace or Business Concerns

  • For internal theft investigations
  • In employee integrity screening (as permitted by law)

Family & Custody Disputes

  • When there are conflicting statements or allegations
  • To support custody claims or verify parenting behavior

Please note: Polygraph examinations in California are conducted privately and may be used to assess the truthfulness of responses to specific questions. However, under California Evidence Code § 351.1, the results of a polygraph examination, the examiner's opinion, or any reference to taking or refusing a polygraph test are not admissible in criminal or civil proceedings unless all parties involved stipulate to their admission.

What to Expect During a Polygraph Test

  1. Pre-Test Interview
    We explain the process, review the facts, and ensure the subject understands and agrees to participate.
  2. Establishing Baselines
    A series of neutral and control questions are asked to identify how the subject responds when answering truthfully.
  3. Administering the Exam
    The subject is asked a set of         yes/no questions related to the issue under investigation.
  4. Post-Test Analysis & Reporting
    Our examiner analyzes the data and provides a clear report that includes findings, supporting data, and a summary of the subject’s responses.

Examinations are conducted in person at a secure and private location.

Mobile polygraph services are available by request throughout Northern CA.

Why Choose Bonnington PI for Polygraph Testing?

Licensed Examiners
All polygraph tests are administered by trained professionals with verified credentials.

Confidential Process
Your results and reasons for testing remain 100% private unless otherwise requested.

Court-Ready Documentation
Detailed reports prepared for attorneys, investigators, or personal peace of mind

Convenient Location
Testing offered in Sacramento, with mobile options across the region

Locations We Serve Across Northern California

Our polygraph exam services are available throughout:

  • Sacramento
  • Roseville
  • Folsom
  • Elk Grove
  • San Francisco Bay Area
  • Greater Sacramento Valley and surrounding counties


We also offer off-site polygraph testing for attorneys, HR departments, and investigative teams in need of confidential or urgent results.

Schedule a Confidential Polygraph Exam Today

Whether you're dealing with legal uncertainty, relationship doubts, or employee dishonesty, a professional polygraph test can give you the clarity you need to move forward.


Call Bonnington PI at (916) 936-7773.
Located in Sacramento, CA—Serving All of Northern California
Fast, confidential, and professionally administered polygraph services

Truth is power. Let us help you find it.