The couple split earlier this year and the custody battle over their 11-month-old daughter turned ugly as Grigorieva rejected a deal to destroy all so-called evidence relating to the break-up in return for $15 million. Sheriff's investigators questioned the methods of the negotiations.
"When attorneys are negotiating a settlement and they are talking back and forth to reach some kind of settlement - is that just negotiating tactics or is it extortion?" asked Steve Whitmore, a spokesman for the sheriff's department.
In an interview with Hollywood.tv Grigorieva said she was not afraid of the extortion charges, saying, "I have never extorted anything from him. There is no proof of any kind. It's all false information that he is feeding the press and it's a smear campaign."
The sheriff's department said the extortion case is complicated and they are several weeks away from presenting their case to prosecutors. They are reviewing emails, text messages and plan to interview a number of involved parties, including Grigorieva.
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