| Business | Phone |
| Callis Investigations 505 Bayou St, Houston 77020 | (713) 222-0681 |
| Michael Monk Investigations 4606 Fm 1960 Rd W 110, Houston 77069 | (281) 893-6665 |
| Worley Group 3107 Orange St, Houston 77020 | (832) 877-2026 |
| Littleton Records Svc 9800 Northwest Fwy, Houston 77092 | (713) 686-3777 |
| Hill Schwartz Spilker Keller 1800 Saint James Pl, Houston 77056 | (713) 739-0600 |
| Investigations Unlimited 1305 Prairie St 201, Houston 77002 | (713) 228-8111 |
| Joe Winter Investigations 1001 Texas St 550, Houston 77002 | (713) 221-1900 |
| Paladin International Inc 440 Louisiana St 1550, Houston 77002 | (713) 864-5000 |
| Premier Protection Group Inc Houston 77002 | (832) 237-9674 |
| Travis Johnson & Assoc 1305 Prairie St, Houston 77002 | (713) 224-8729 |
| Paramount Document Retrieval 330 Garden Oaks Blvd, Houston 77018 | (713) 869-9050 |
| R J Vargas Investigations 535 North Loop, Houston 77018 | (713) 226-8094 |
| Timothy E Acker 12625 Memorial Dr, Houston 77024 | (713) 984-9229 |
| Wayne Wicks & Assoc 3637 W Alabama St 100, Houston 77027 | (713) 439-1896 |
| P I Inc 11821 East Fwy 140, Houston 77029 | (713) 451-2010 |
| Marker Group Inc 13105 Northwest Fwy 300, Houston 77040 | (713) 460-9070 |
| Clyde Wilson Investigations 7211 Long Point Rd, Houston 77055 | (713) 467-0483 |
| Tim D Wilson Investigations 7211 Long Point Rd, Houston 77055 | (713) 956-1111 |
| Lords Of London Security 5433 Westheimer Rd, Houston 77056 | (713) 961-3636 |
| Robert Grieve Intl Inc 4900 Woodway Dr 550, Houston 77056 | (713) 963-9916 |
| Van Meter & Assoc Llp 5151 San Felipe St, Houston 77056 | (713) 552-0401 |
| Icu Investigations 5959 Westheimer Rd, Houston 77057 | (713) 957-1911 |
| Sys Information Inc 2620 Fountain View Dr, Houston 77057 | (832) 242-2588 |
| Lowry & Assoc 505 N Sam Houston Pkwy E 550, Houston 77060 | (281) 260-7935 |
| Spiegelhauer & Assoc 11811 North Fwy, Houston 77060 | (281) 591-4700 |
| Taylor Investigation 525 N Sam Houston Pkwy E, Houston 77060 | (281) 651-0326 |
| Ils Technologies 5629 Fm 1960 Rd W 221, Houston 77069 | (281) 444-1511 |
| Roehling & Roehling Invstgtns 11767 Katy Fwy 920, Houston 77079 | (281) 558-1188 |
| Rsi Ross Security & Invstgtn 11511 Katy Fwy, Houston 77079 | (281) 752-0911 |
| Spy Emporium-Gadgets & Equip 6065 Hillcroft St 407, Houston 77081 | (713) 774-1005 |
| Resource Investigation 18011 Garden Manor Dr, Houston 77084 | (713) 627-7057 |
| Y Rn Investigations 3706 Belk St, Houston 77087 | (713) 353-4017 |
| Mc Lain & Patterson Invstgtn Houston 77090 | (281) 397-0605 |
| U S Protection & Investigation 11500 Northwest Fwy 612, Houston 77092 | (713) 681-1180 |
| River Oaks Investigations 3262 Westheimer Rd 122, Houston 77098 | (713) 520-0508 |
| Skyy Tracing Svc Houston 77098 | (713) 529-7599 |
| Bayou City Investigations Po Box 61646, Houston 77208 | (281) 437-3337 |
| Pazda & Assoc Po Box 20707, Houston 77225 | (713) 660-0630 |
| Parker Private Investigations 1314 Texas St, Houston 77002 | (713) 223-5656 |
| Research World Unlimited 1603 Fannin St, Houston 77002 | (713) 869-7300 |
| S H Belshaw & Assoc Invstgtn 1305 Prairie St 300, Houston 77002 | (713) 227-6667 |
| Stan Lewis & Assoc 700 Louisiana St 2447, Houston 77002 | (713) 225-3110 |
| Stapp Singleton Inc 1415 Louisiana St, Houston 77002 | (713) 951-9500 |
| Texas Investigative Network 5225 Katy Fwy 525, Houston 77007 | (713) 807-8811 |
| R J Vargas Investigations 3700 N Main St, Houston 77009 | (713) 426-0022 |
| Noukas & Assoc 2323 S Shepherd Dr 920, Houston 77019 | (713) 520-9191 |
| Southwest Investigation 1906 Park St, Houston 77019 | (713) 529-2224 |
| Phillips Investigations 908 Town & Country Blvd 120amp;, Houston 77024 | (281) 855-6058 |
| Texas Special Investigators 1229 Buschong St, Houston 77039 | (281) 442-7487 |
| Rapid Results Investigation 2656 South Loop W, Houston 77054 | (713) 661-1033 |
| P M Clinton Intl Investigation 7201 Westview Dr, Houston 77055 | (713) 686-6864 |
| Pannell Investigations 5712 Val Verde, Suite 250, Houston 77057 | (713) 975-0505 |
| Trackers Inc 6060 Richmond Ave 170, Houston 77057 | (713) 782-5999 |
| Turman & Assoc Inc 1100 Nasa Rd 1 501, Houston 77058 | (281) 335-1600 |
| Otis Owens Worldwide Invstgtns 525 N Sam Houston Pkwy E 545, Houston 77060 | (281) 987-1129 |
| Skaggs & Assoc Inc 7500 San Felipe St 600, Houston 77063 | (713) 781-9040 |
| Patillo Investigation Co 11603 Old Telegraph Rd, Houston 77067 | (281) 893-1066 |
| Stadler & Co 3724 Fm 1960 Rd W 242, Houston 77068 | (281) 444-3434 |
| Wheeler Investigative Resource 1920 Sedgie Dr, Houston 77080 | (713) 722-7722 |
| Pipkins Investigation Co 9800 Northwest Fwy 306, Houston 77092 | (713) 682-1133 |
| Precision Records Inc 9800 Northwest Fwy 306, Houston 77092 | (713) 681-3003 |
| Southern Comfort Security Svc 10101 Fondren Rd 256, Houston 77096 | (713) 981-7224 |
| Stewart & Assoc 10103 Fondren Rd 238, Houston 77096 | (713) 779-3432 |
| Wheeler Group Inc Po Box 801613, Houston 77280 | (713) 722-0474 |