| Business | Phone |
| Allied Investigating Agency 311 Quilting Way, Bel Air 21015 | (410) 515-9900 |
| Corporate Security Svc Bel Air 21014 | (410) 836-5926 |
| Hall Investigations Po Box 595, Bel Air 21014 | (410) 879-1117 |
| Harford Bureau-Investigation 125 N Main St, Bel Air 21014 | (410) 893-4610 |
| Paragon Investigative & Scrty 16 N Hays St, Bel Air 21014 | (410) 838-0959 |
| R Marts & Assoc Bel Air 21014 | (443) 336-2027 |