Minneapolis GOP donor Anton Lazzaro, indicted on federal child sex-trafficking charges, appeared in federal court Thursday to argue that agents improperly listened to jail phone calls between him and his attorneys.

Awaiting trial on 10 counts, Lazzaro has been held in Sherburne County jail for nearly a year. In June, his attorneys asked Chief U.S. District Judge Patrick Schiltz to dismiss the indictment or bar those aware of the phone calls' contents from further involvement in the case. Federal prosecutors have since argued that there is no basis to dismiss the case or impose sanctions because the government did not intentionally access his privileged calls.

Daniel Gerdts, an attorney for Lazzaro, wrote in a court filing that records obtained from the company that manages Sherburne County's jail phone system showed FBI and state Bureau of Criminal Apprehension agents accessed and listened to seven privileged calls between Lazzaro and his attorneys.

Gerdts said that the interception of privileged attorney-client communication violated Lazzaro's Fifth Amendment right to a fair proceeding and Sixth Amendment right to the effective assistance of counsel.

"Once Mr. Lazzaro and his attorneys became aware that their calls were not private, it immediately inhibited the effectiveness of their telephonic communications," he wrote in June.

Assistant U.S. Attorney Melinda Williams meanwhile countered this month that there was no basis to dismiss charges or impose sanctions because "no evidence exists to show that the government intentionally intruded into the defendant's attorney-client communications or that the defendant suffered any prejudice from any limited, inadvertent disclosure of his attorney-client communications."

Williams said that law enforcement has since paused listening to any of Lazzaro's calls.

Lazzaro, wearing an orange prison jumpsuit, appeared in person alongside his attorneys in Minneapolis on Thursday.

Mary Cunningham, a tactical specialist for the FBI, and Susan Webb, criminal intelligence analyst for the state Bureau of Criminal Apprehension, both testified that they took steps to avoid listening to Lazzaro's calls with attorneys and that they knew the importance of not accessing the privileged calls.

Prosecutors said six of the calls accessed by the FBI were the result of inadvertent "mis-clicks" on a spreadsheet of calls in which Cunningham selected calls associated with an attorney's phone number that hadn't been identified as such.

Cunningham immediately closed out of the recordings, according to the court filing. The seventh recording in question was accessed by the BCA analyst, who listened to 10 seconds of a call before closing the recording upon hearing a name similar to one of Lazzaro's attorneys.

Lazzaro is charged with conspiracy to commit sex trafficking of minors, five counts of sex trafficking of minors, one count of attempted sex trafficking of a minor and three counts of obstruction of justice. He was charged alongside former University of St. Thomas student Gisela Castro Medina. Medina is accused of recruiting underage girls for a sex-trafficking conspiracy she participated in with Lazzaro. Both have pleaded not guilty.