Seller autobidding to raise price?

I have a seller who sells the same brand/model item 2-3 times daily. I've been watching over 30 of these items over the last 3 weeks waiting for a price point that I think is right. It seems that with about 2 hours or less remaining in the auction, somebody bids $91. Ebay hides the seller's account, but it seems to be a different user account each time. Is it against policy for a seller to use a program to login as a user and auto bid to bring the price up to a certain price point? It's just too obvious that different buyers are bidding the exact same price towards the end of the auction. How do I report a seller on suspician of this activity?|||It's not strange for a like item to get near-identical bids and sell for the same average price every time! If you click the mystery bidders you can see what percentage of bids they've placed with that seller. And you can share a closed listing number for us to look at.~James~