How would you verify whether someone requesting graphic design work actually works for the company he claims needs my services?

How would you verify whether someone requesting graphic design work actually works for the company he claims needs my services?

I got a message from someone who claims he is the executive director (CEO) of a company. He wants graphic design work from me. When I look at his LinkedIn page, it says he is the Executive Director, but when I call the company directly to ask if that is correct, they won't give out that information because of the nature of my request. I guess if I was calling to hire him for some sort of service, they could give me that information, but since he is requesting service from me, they can't tell me whether the name I provide them has any affiliation with the company.

Is there any other way of verifying this guy actually holds a position of executive director within the company? Typical Google searching provides nothing for me.

Thanks for any help given!