| Business | Phone |
| Huntington Research Assoc Ltd 225 S Troy St 210, Royal Oak 48067 | (248) 544-2020 |
| Tim Lennon Investigations Royal Oak 48073 | (248) 585-2079 |
| Bureau Of Confidential Investi 1316 N Campbell Rd, Royal Oak 48067 | (248) 546-1001 |
| Ryan R Robison & Co 25600 Woodward Ave, Royal Oak 48067 | (248) 582-8110 |