| Business | Phone |
| A Woman-Owned Private Fairfax 22031 | (703) 205-9692 |
| Axcel Security Agency Inc Fairfax 22030 | (703) 385-5961 |
| Cdi Venator Llc 10482 Armstrong St, Fairfax 22030 | (703) 385-1667 |
| Checkmate Investigation Inc 4031 Chain Bridge Rd, Fairfax 22030 | (703) 352-6174 |
| Corporate Intelligence Rsrchrs 4242 Chain Bridge Rd # A, Fairfax 22030 | (703) 425-1200 |
| Donald L Koch Ltd 10605 Judicial Dr, Fairfax 22030 | (703) 691-2040 |
| Investigative Services Fairfax 22030 | (703) 273-4526 |
| East Coast Investigation Fairfax 22030 | (703) 383-9446 |
| F & S Investigations 10332 Main St, Fairfax 22030 | (703) 934-0014 |
| In Defense 10332 Main St 181, Fairfax 22030 | (540) 955-3950 |
| Indefense Inc 10332 Main St 181, Fairfax 22030 | (703) 293-6262 |
| Infonation 10560 Main St, Fairfax 22030 | (703) 278-9090 |
| Interprobe 11094 Lee Hwy, Fairfax 22030 | (703) 385-0336 |
| Joan M Beach Ltd 4242 Chain Bridge Rd, Fairfax 22030 | (703) 359-8084 |
| O'Connell & Assoc Inc 11166 Main St 301, Fairfax 22030 | (703) 273-7714 |
| Shamus Inc 10511 Judicial Dr # C1, Fairfax 22030 | (703) 437-8670 |
| Spy Guys Inc 10195 Main St, Fairfax 22031 | (703) 803-6152 |
| Vernon Kirby 4242 Chain Bridge Rd A, Fairfax 22030 | (703) 691-4868 |
| Lawrence Investigations 4912 Heversham Ct, Fairfax 22032 | (703) 425-7833 |