The extortion investigation was launched in connection to the $15 million deal she signed -- and then rejected -- during child custody mediation with Mel Gibson in May, 2010.
In the deal, Oksana was promised a house, assets and other goodies ... plus the guarantee she wouldn't release the infamous audio tapes.
A rep for Grigorieva released a statement saying in part, "Ms. Grigorieva will now concentrate on co-parenting Lucia, resuming her charitable work for the children of Chernobyl and moving forward with her life."
Oksana Grigorieva NOT Charged | TMZ.com
