TMZ has learned a detective from the L.A. County Sheriff's Department now has CDs of the conversations Oksana Grigorieva recorded.
We've learned the detective is assigned to the domestic violence part of the investigation. There are other detectives -- also present in court -- who are investigating allegations of child endangerment.
Sheriff's spokesperson Steve Whitmore tells TMZ, "The court released the audio tapes to our detective handling the domestic violence investigation. Those tapes will now be reviewed and analyzed by our detectives as well as forensic detectives."