The attorney who is defending accused murder mom CASEY ANTHONY is now under investigation by authorities himself!

The Florida Bar Association is conducting an open investigation into Casey Anthony’s lead defense attorney, Jose Baez.

"Yes, there is an open file. It will remain confidential unless or until probable cause is found. The bar is looking into it," a spokeswoman for the Florida Bar, Karen Kirksey told WESH-TV.

Baez will attempt to create "reasonable doubt" in the mind of jurors when the sensational murder trial of Casey Anthony begins in May was fined this past December by Judge Blevins for not complying with a court order.

Legal analysts said a fine would not trigger an internal bar investigation dealing with presumed ethical infractions.

Docs released last week  by the State Attorney’s Office in the case against Anthony reveal a parallel tampering investigation was launched into the statements of a defense witness.

The target of the investigation was not named nor  were charges were filed.

Casey Anthony remains behind bars accused of murdering her 2 year old daughter Caylee in 2008.