Criminal Defense Investigator: Is a PI License Required?

A criminal defense investigator finds and documents facts for the defense in a criminal case. The work is locating and interviewing witnesses, checking police reports and evidence, writing up findings and testifying about them. Public defender offices, which represent defendants who cannot afford a lawyer, hire them directly. Private defense law firms retain them too.

Fulton County, Georgia's public defender posting lists the daily work: supporting assistant public defenders, locating witnesses, serving subpoenas, transporting clients and attorneys, preparing investigative documents and testifying in court.

A defense investigator is not a police detective. The BLS notes that private detectives and investigators have no police authority and follow the same laws as any private citizen.

No, not for public defender investigator jobs. None of the eight postings and job classifications below requires a PI license, and all eight name a valid driver's license instead. For private defense work, state law decides, as the next section shows.

The eight entries were compiled in October 2026 and are dated 2023 to 2026, and several are now closed. They show how defender offices write requirements, not what is open today.

Six of the eight (San Francisco, Contra Costa, San Bernardino, Fulton, Colorado, Santa Cruz) accept a route without a bachelor's degree. Contra Costa's route needs 60 college units and Santa Cruz's needs 2 years of college. Fulton's route is an unspecified "equivalent combination." Only San Francisco, San Bernardino and Colorado are clearly open with no college at all. DC and Miami-Dade name a bachelor's degree.

A PI license matters when you take defense cases as a private investigator, because the BLS reports that most states require private detectives and investigators to be licensed. Whether an investigator employed by an attorney is exempt differs by state, so the answer depends on where you work and how you are engaged. Our state-by-state guide to private investigator license requirements shows where your state stands.

• Texas. The Department of Public Safety Private Security Program licenses investigators under Occupations Code Chapter 1702. Attorney General Opinion GA-0275 (2004) concluded that an employee working under an exempt attorney's direct supervision does not need an investigations license.
• Georgia. The Board of Private Detective and Security Agencies licenses private detective businesses under Title 43, Chapter 38. Section 43-38-14 lists the exceptions, which include persons employed only in connection with a single employer's affairs.
• Minnesota. Minnesota Statutes 326.3381 bars anyone from engaging in the business of private detective without a license from the Private Detective and Protective Agent Services Board. It exempts a proprietary employer from needing its own license.

Our inference: a staff investigator employed by the defending attorney or firm is more likely to be exempt than a freelancer billing several firms, who carries the licensing risk. Our recommendation: before accepting paid work, ask your state board in writing whether your arrangement requires a license.

Starting pay in seven posted defender roles (2023 to 2026, several now closed) ran from $39,000 to $115,544 a year, with a median of $64,792. That median is our figure from a small sample. The BLS reports a May 2025 median of $51,220 for all private detectives and investigators, across 39,500 jobs.

Our model, with the working shown. We used the seven table roles that state pay and took the lowest figure of each range. Colorado's $5,540 a month times 12 is $66,480. Sorted, the seven starts are $39,000, $60,185, $61,380, $64,792, $66,480, $109,338 and $115,544. The fourth of seven is the median: $64,792.

Treat it with care. Seven postings is a small sample, and two are California offices that pull the top end up. Colorado's figure is for one named position. Miami-Dade's $39,000 is a starting figure that can rise with qualifications. The BLS figure covers every pay level and every kind of private investigator, so the two numbers are not like-for-like. Ceilings are separate from starts: the highest top step in the table is $140,452 in San Francisco.

Check six things in order: the license line, the entry route, the degree line, any trainee clock, the annualized pay, and the vehicle requirement. Each is a test with a clear result.

Defense Investigator Posting Check

Which posting type fits your background?

Our inference: a writing sample improves any application, because the postings put preparing investigative documents among the core duties. Our guides on writing investigation reports that hold up and interview techniques for investigators show how to build one.

No. Neither credential appeared in the minimum qualifications of the eight postings, and both require years of experience before you can apply, so they follow the job.

The CLI comes from the National Association of Legal Investigators. Requirements include five years of verifiable work experience as a legal investigator, with 60 college semester hours substituting for one year. You also submit a white paper of at least 1,000 words and pass an oral exam and a written exam. You need 70% or more in each of the three parts. Renewal runs in three-year periods with continuing education credits.

The CCDI comes from the Criminal Defense Investigation Training Council. Requirements include two years as a criminal defense investigator, either in a public defender's office or as a licensed private investigator, and 25 documented, comprehensive assignments. You also need two recommendations from defense counsel and a written test. Training of 16 hours, 8 hours (fast track) or approved distance learning must be used toward certification within five years of completion. The fee is $225, which includes first-year membership, or $175 for current paid members. Maintaining it takes 10 continuing education units every two years.

Our recommendation: start a case log from your first assignment, since the CCDI asks for 25 documented assignments and the log is hard to rebuild later.

Training that covers criminal law, evidence, interviewing and testimony matches the duties in the postings. Our Criminal Defense Investigation course costs $120 as of October 2026. It runs 8 hours across 63 lessons with 12 assessments (136 questions) and ends in a certificate of completion. The course is self-paced online.

It covers the roles of the investigator, defender, defendant and prosecutor, how the criminal courts operate, defenses to criminal charges, defendant's rights, reconstructing the scene, interviewing witnesses, forensic testing, evaluating the police investigation, chain of custody, search and seizure, evidence admissibility and testifying.

The course page lists approval in Missouri, Minnesota, Kansas, Iowa, Oregon, South Carolina, Oklahoma, Kentucky, Tennessee, New Mexico, Texas, North Carolina and Georgia, with North Carolina credit limited to 6 continuing education units. State approvals cover PI continuing education only and do not count toward CLI or CCDI requirements. Our guide to checking whether a PI course counts in your state walks through confirming it with your own state board.

Individuals can enroll on the course page. For a corporate account, call 706-268-2221 or 832-922-1215, Monday to Friday, 9 AM to 6 PM Eastern.