| Business | Phone |
| Tri-State Investigative Svc 2025 S Washington Ave 310, Lansing 48910 | (517) 485-4131 |
| Cook Detective Agency 1115 Bretton Rd, Lansing 48917 | (517) 886-3786 |
| Research Consultants Group Inc Po Box 27397, Lansing 48909 | (517) 272-5422 |
| Research North Inc 416 N Homer St 101, Lansing 48912 | (517) 332-4300 |
| Don Brooks Investigations Po Box 80822, Lansing 48908 | (517) 321-1782 |
| Earegood Court Svc 4811 Lyncott Dr, Lansing 48910 | (517) 887-8008 |