As a Special Agent, I investigated a case where an employee was conspiring with a vendor and stole several thousands of dollars. The vendor set up several businesses and obtained EINs for those businesses. The employee then set up the companies in the system and the vendor provided the company with fictitious invoices for services that were not provided.

An obvious red flag was the vendor had the same address and phone number for the different entities in the system.

What are some other possible red flags related to vendor fraud?