| Business | Phone |
| Athey & Assoc Inc Po Box 1302, Columbia 21044 | (410) 531-7550 |
| Checkmate Independent Adjuster 10840 Little Patuxent Pkwy, Columbia 21044 | (301) 596-7173 |
| Donaldson Investigations Ltd Columbia 21044 | (410) 997-0519 |
| Flagship Investigations Inc 8970 State Route 108 # F, Columbia 21045 | (410) 997-3264 |
| Flagship Security Svc 8970 State Route 108 # F, Columbia 21045 | (410) 720-0977 |
| High Tower Investigative Grp 5305 Night Roost Ct, Columbia 21045 | (410) 992-4796 |
| John Roche Investigations Po Box 266, Columbia 21045 | (410) 893-2659 |
| Lewis J Neuwelt Investigations 9175 Guilford Rd, Columbia 21046 | (301) 604-5135 |
| E J Morey Columbia 21044 | (410) 740-3471 |
| Velez & Assoc 8775 Centre Park Dr # 527, Columbia 21045 | (410) 997-1755 |