signs of ext price manipulation

What are the signs of EXT price manipulation that you have seen?

I have observed that the SP seems to go down on very small trades like:

down 7 cents for a one share trade!
10/19/09 11:05:07 9.98 4197
10/19/09 11:08:47 9.91 1

down 3 cents for a three share trade!
10/19/09 14:12:38 9.83 159
10/19/09 14:14:12 9.80 3
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I have also noticed very low SP before the market opens!
-- The indictive SP was $9.30 (prior day close was $9.40)

-- The actual SP upon opening was $9.30 for the opening trades.

SELLERS
Price Qty.. Orders
8.84 1,030 1
9.17 1,076 1
9.30 4,085 2
9.47 500.. 1