Lynn Z,
I am not sure if your question was ever answered, but in THEORY, there could be a number of reasons why an Investor(s) may bid so high on a property (see below).
POSSIBLE REASONS---Again---POSSIBLE REASONS ONLY:
They have researched the value of the property and realize that it is worth it: to bid so High/bidding that High/making that kind of Investment, or
DEPENDING on the State/County, the Investor(s) realize the owner or anyone who may have an interest in redeeming the property is less likely to do so (that is, less likely to redeem it)----or,
It may very well have been a scare tactic (to distract the competition). In some cases, you may want to check back with the City, County, etc.. to see if in fact the bid was ever submitted or if the Property will be re-auctioned at a later date.
Finally, if you have the courage (not to say that you do not), but if you do, Ask the Investor what attracted them to that property and why did they see it as a good Investment. Let them know you are learning. It may be worth asking, but do not be surprised if they are somewhat reluctant to share that information. After all, they are Investing Real Dollars & With A Good Sense of knowing what they are doing---in some cases!
Again, without know all of the specific details, these are just a possible/suggested reasons (in theory), in general. I hope this helps.
Much Success As You Invest!