Obviously, someone has a concern here, however, I seriously doubt that you could provide any relavent information that would positively prove a shill bidding activity, and in trying to do so, you will potentially lay yourself open for some real liability.

eBay has a complaint process that this person can file a claim through, not to mention the Claims process (your first two options) either one of which (or both) the person you are representing has the ability to act upon.

Option 3 will resolve nothing and will only lead to trouble.

In my opinion, some things are best left to those who know what they are doing and have a responsibility.

Respectfully,

Jim Follis