An internal auditor conducted interviews with several employees, documented the interviews analyzed the summaries, and...

The internal auditor has primarily obtained testimonial evidence. Testimonial evidence is derived from interviews, discussions, and responses from employees or other parties. It involves collecting and analyzing verbal information to draw conclusions, which is precisely what the auditor did by conducting interviews, documenting them, analyzing the summaries, and drawing conclusions based on this information.

IIA Standards: 2310 - Identifying Information

IIA Practice Guide: Audit Evidence