| Business | Phone |
| Andersen & Assoc 10 E Mulberry St, Baltimore 21202 | (410) 752-3927 |
| Maryland Claims Investigations Baltimore 21236 | (410) 256-6161 |
| Corporated Intl Business Ctr 7305 Belair Rd, Baltimore 21206 | (410) 665-0800 |
| Osh Operative Security Agncy 3014 Ferndale Ave, Baltimore 21207 | (410) 448-2578 |
| Pdq Private Investigation 429 Eastern Blvd, Baltimore 21221 | (410) 574-5168 |
| Donaldson Investigations Ltd Baltimore 21212 | (410) 323-0308 |
| R L Oatman & Assoc 600 Fairmount Ave # 101, Baltimore 21286 | (410) 494-1126 |
| Randisi & Assoc Inc 806 Chestnut Glen Garth, Baltimore 21204 | (410) 494-0232 |
| Marvin G Kane Electronic Count Baltimore 21212 | (410) 323-2455 |
| Aarrow Security Analysts Inc Baltimore 21228 | (410) 869-8644 |
| Nsa Research 25 Light St, Baltimore 21202 | (410) 605-9630 |
| Atlas Investigations Inc Po Box 9672, Baltimore 21237 | (410) 687-9556 |
| Robinson Detective Agency 111 E 25th St, Baltimore 21218 | (410) 235-2900 |
| Street Group Inc 110 E Lexington St, Baltimore 21202 | (410) 332-0069 |
| Commercial Index Bureau Inv 5205 East Dr # O, Baltimore 21227 | (410) 242-8150 |
| Cotton & Krahling Special Svc 7125 Harford Rd, Baltimore 21234 | (410) 254-8600 |
| Tontine Group Baltimore 21202 | (410) 659-7171 |
| Data Technology Security Baltimore 21220 | (410) 944-3200 |
| Donaldson Investigations Ltd Baltimore 21204 | (410) 321-1520 |
| Executive Investigation Bureau 7119 Harford Rd, Baltimore 21234 | (410) 444-9223 |
| L H Levy Investigations Inc 4110 Villa Nova Rd, Baltimore 21207 | (410) 653-9025 |
| World Investigative Svc 701 Wilson Point Rd # 6-605, Baltimore 21220 | (410) 682-5563 |
| World Investigators Network 7501 Sparrows Point Blvd, Baltimore 21219 | (410) 477-8879 |