Short, sweet, and to the point -- Oksana Grigorieva flat out called Mel Gibson a liar this morning.
Oksana -- who denies her sister was the one who leaked the infamous tapes -- isn't nearly as long-winded as Mel is.
Oksana -- Mel Gibson Is a Liar!
7/23/2010 4:01 PM PDT BY TMZ STAFF
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