Company lists · Data refreshed September 2026

Top 25 Investigator recruitment firms based in the United States

Name: Investigator recruitment firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 28, 2026 1,654 companies tracked

RevenueBase identified 1,654 investigator recruitment firms headquartered in the United States as of September 2026 and tracks 19,880 professional contacts across them, including 3,094 with verified work emails. New York is the largest hub.

This list covers investigator recruitment firms headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 28, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 28, 2026 86% judged on-target in blind review

1,654Companies

19,880Contacts tracked

3,094Verified emails

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The 25 largest investigator recruitment firms based in the United States

Ranked by team size

Top 25 of 1,654 investigator recruitment firms based in the United States, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to investigator recruitment firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	US Security Association INC	Indirect evidence	Joplin, MO, United StatesHQ checked Sep 28, 2026	n/a	981 contacts →
	Indirect evidence “US Security Association Inc is a law enforcement company based out of 2914 E 32nd St, Joplin, Missouri, United States.” Source: RevenueBase Database · checked Sep 28, 2026
2	Omniplex World Services Corporation	Partial evidence	Herndon, VA, United StatesHQ checked Sep 28, 2026	1,001-5,000	677 contacts →
	Partial evidence “OMNIPLEX World Services Corporation is a leader and innovator in delivering professional background investigations, intelligence support, and physical security services to…” Source: RevenueBase Database · checked Sep 28, 2026
3	Professional Security Consultants, INC	Partial evidence	Los Angeles, CA, United StatesHQ checked Sep 28, 2026	1,001-5,000	626 contacts →
	Partial evidence “Professional Security Consultants, Inc.(PSC) is a world-class provider of security guard services, patrol, investigations, backgrounds, consulting, security screening & specialty…” Source: RevenueBase Database · checked Sep 28, 2026
4	DK Security	Partial evidence	Grand Rapids, MI, United StatesHQ checked Sep 28, 2026	1,001-5,000	572 contacts →
	Partial evidence “DK Security is unique in that it offers a single company for a wide ranging availability of security and investigative services.” Source: RevenueBase Database · checked Sep 28, 2026
5	Ranger American	Partial evidence	San Juan, United StatesHQ checked Sep 28, 2026	1,001-5,000	511 contacts →
	Partial evidence “Founded in 1982, Ranger American is a professional security organization with an extensive background in the security and investigation fields.” Source: RevenueBase Database · checked Sep 28, 2026
6	American Security & Investigations	Partial evidence	St. Paul, MN, United StatesHQ checked Sep 28, 2026	1,001-5,000	404 contacts →
	Partial evidence “American Security & Investigations has provided security and investigative services throughout the upper midwest since 1959.” Source: RevenueBase Database · checked Sep 28, 2026
7	Digistream Investigations	Partial evidence	Davis, CA, United StatesHQ checked Sep 28, 2026	201-500	327 contacts →
	Partial evidence “DigiStream Investigations is a full-service private investigation firm specializing in insurance defense and legal support services.” Source: RevenueBase Database · checked Sep 28, 2026
8	Apple & Associates	Indirect evidence	Warrenville, SC, United StatesHQ checked Sep 28, 2026	n/a	305 contacts →
	Indirect evidence “Apple & Associates is an executive search firm serving the following industries: Medical Device, Life Science, Pharmaceutical, Software, Government and National Laboratories and…” Source: RevenueBase Database · checked Sep 28, 2026
9	HUB Enterprises, INC	Partial evidence	Broussard, LA, United StatesHQ checked Sep 28, 2026	501-1,000	292 contacts →
	Partial evidence “HUB Enterprises is a national insurance defense investigative firm.” Source: RevenueBase Database · checked Sep 28, 2026
10	ADC LTD NM	Partial evidence	Albuquerque, NM, United StatesHQ checked Sep 28, 2026	501-1,000	252 contacts →
	Partial evidence “ADC supports government and corporate clients with two primary services - personnel security, ranging from pre-employment checks to comprehensive background investigations and…” Source: RevenueBase Database · checked Sep 28, 2026
11	Frasco	Partial evidence	Irvine, CA, United StatesHQ checked Sep 28, 2026	201-500	214 contacts →
	Partial evidence “Frasco has hundreds of investigators and regional offices located throughout the country.” Source: RevenueBase Database · checked Sep 28, 2026
12	Advantage Investigations	Partial evidence	Kannapolis, NC, United StatesHQ checked Sep 28, 2026	201-500	214 contacts →
	Partial evidence “Advantage Investigations is a nationwide leader in the industry for investigative services.” Source: RevenueBase Database · checked Sep 28, 2026
13	St. James Security Services, INC	Indirect evidence	San Juan, United StatesHQ checked Sep 28, 2026	51-200	211 contacts →
	Indirect evidence “St.” Source: RevenueBase Database · checked Sep 28, 2026
14	American Security Programs	Indirect evidence	Reston, VA, United StatesHQ checked Sep 28, 2026	1,001-5,000	172 contacts →
	Indirect evidence “ASP is a premium contract security services company based in Northern Virginia and a wholly owned subsidiary of SecurAmerica.” Source: RevenueBase Database · checked Sep 28, 2026
15	Anderson Security Agency	Indirect evidence	Phoenix, AZ, United StatesHQ checked Sep 28, 2026	201-500	164 contacts →
	Indirect evidence “Anderson Security is a 23 year old, locally women-owned (National Women's Business Enterprise Certification) and operated security company that provides security officers…” Source: RevenueBase Database · checked Sep 28, 2026
16	Movement Search & Delivery	Indirect evidence	Clarkston, MI, United StatesHQ checked Sep 28, 2026	51-200	156 contacts →
	Indirect evidence “MOVEMENT is a recruiting and search firm with global reach.” Source: RevenueBase Database · checked Sep 28, 2026
17	Beau Dietl & Associates	Partial evidence	New York, NY, United StatesHQ checked Sep 28, 2026	51-200	129 contacts →
	Partial evidence “Beau Dietl & Associates is a premier private investigation firm based in New York City with offices in New Jersey, Florida, and California.” Source: RevenueBase Database · checked Sep 28, 2026
18	Crawford Thomas Recruiting	Indirect evidence	Orlando, FL, United StatesHQ checked Sep 28, 2026	51-200	126 contacts →
	Indirect evidence “Crawford Thomas Recruiting is a nationwide recruiting and staffing firm recognized for exceeding client expectations regarding time to fill, value and quality of candidates.” Source: RevenueBase Database · checked Sep 28, 2026
19	Long Ridge Partners	Partial evidence	New York, NY, United StatesHQ checked Sep 28, 2026	11-50	120 contacts →
	Partial evidence “Founded in 2004, Long Ridge Partners is a leading recruitment firm serving the alternative investment industry, partnering with hedge funds, private equity firms, real estate…” Source: RevenueBase Database · checked Sep 28, 2026
20	Alias Intelligence	Partial evidence	Los Angeles, TX, United StatesHQ checked Sep 28, 2026	51-200	107 contacts →
	Partial evidence “Alias Intelligence is a leading background investigations and due diligence company delivering the information and insights our clients need to grow and navigate their businesses.” Source: RevenueBase Database · checked Sep 28, 2026
21	The Richmond Group USA	Indirect evidence	Henrico, VA, United StatesHQ checked Sep 28, 2026	11-50	97 contacts →
	Indirect evidence “As we celebrate our 59th year in business, The Richmond Group USA (TRG) has built its reputation as one of the nation’s most established and successful recruiting firms.” Source: RevenueBase Database · checked Sep 28, 2026
22	Becker & Company, INC	Indirect evidence	United StatesHQ checked Sep 28, 2026	201-500	94 contacts →
	Indirect evidence “Why Becker & Company?” Source: RevenueBase Database · checked Sep 28, 2026
23	Lateral Link	Partial evidence	Los Angeles, CA, United StatesHQ checked Sep 28, 2026	51-200	92 contacts →
	Partial evidence “Our team of legal recruitment specialists excels in providing placement services for law firms, in-house legal departments, and staffing needs.” Source: RevenueBase Database · checked Sep 28, 2026
24	Black BOX Security, INC	Indirect evidence	Los Angeles, CA, United StatesHQ checked Sep 28, 2026	51-200	91 contacts →
	Indirect evidence “Black Box Security Inc.” Source: RevenueBase Database · checked Sep 28, 2026
25	American Heritage Protective Services, INC	Indirect evidence	Alsip, IL, United StatesHQ checked Sep 28, 2026	201-500	89 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 28, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: investigator recruitment firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names investigator recruitment firms.
Partial evidence: Its own public description names part of investigator recruitment firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name investigator recruitment firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 1,654 investigator recruitment firms based in the United States

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Investigator recruitment firms based in the United States at a glance

As of Sep 28, 2026

15.6%Verified-email coverage

12.0Average contacts per company

1-10Median size (employees)

4.7%Largest-city concentration · New York

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

1,052

11-50

405

51-200

135

201-500

501-1,000

1,001-5,000

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 1,654 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among investigator recruitment firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in the United States whose own description of what they do matches “investigator recruitment firms”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names investigator recruitment firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among investigator recruitment firms, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 3,094 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 28, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Investigator recruitment firms by metro

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names investigator recruitment firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many investigator recruitment firms are there based in the United States?

RevenueBase identified 1,654 investigator recruitment firms headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

US Security Association INC, headquartered in Joplin, tops this list with the largest team on record.

Which city has the most investigator recruitment firms?

New York leads with 77 headquartered companies, followed by Houston (36) and Chicago (30).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 3,094 verified decision-maker contacts tracked across these 1,654 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 28, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.