| Business | Phone |
| Bear Creek Investigations Inc Billings 59102 | (406) 670-4534 |
| Belcher & Belcher Billings 59102 | (406) 248-2652 |
| Dunbar & Assoc 1645 Avenue D # I, Billings 59102 | (406) 252-2353 |
| R C Investigations Po Box 21606, Billings 59104 | (406) 652-7599 |
| Ronald Maki Investigations 1145 Central Ave, Billings 59102 | (406) 256-9500 |
| Ronald Maki Investigations 2708 Montana Ave, Billings 59101 | (406) 256-9500 |
| Pro Investigations 1148 1st Ave N, Billings 59101 | (406) 256-9525 |
| Hinz Enterprises Billings 59101 | (406) 698-7610 |
| Investigation Security Bureau 208 N 29th St # 225, Billings 59101 | (406) 259-6656 |
| Investigations Plus Po Box 20806, Billings 59104 | (406) 656-8340 |
| Investigative Research Assocs Po Box 80466, Billings 59108 | (406) 690-5134 |
| K Barth Private Investigation 2760 Avalon Rd, Billings 59102 | (406) 652-0931 |