In court papers filed Wednesday, investigator Steven Jacobson said the calls were discovered Friday by an expert from the software company that designed the wiretap system. The two men listened to about 10 seconds of one of the calls to determine that hidden computer files contained actual phone calls and not a dial tone or dead air.
"We heard a person in a Southern drawl talking to Scott Peterson in what appeared to be a business-related call," Jacobson wrote in an affidavit.
Jacobson said he had not heard that conversation before among the 3,858 phone calls police previously acknowledged logging on the fertilizer salesman's home and cellular phones. He said he didn't listen to any others before having them transferred to computer discs and sealed in envelopes for Superior Court Judge Al Girolami to review.
The newly discovered calls could present another hurdle for prosecutors as they fight defense claims of prosecutorial misconduct over the wiretaps. When word of the previous wiretaps came out, defense lawyer Mark Geragos asked the judge to dismiss the prosecutors handling the case or toss out the wiretaps because investigators listened to portions of conversations between Peterson and his lawyer.
Peterson, 30, has pleaded innocent to two counts of murder and could face the death penalty if convicted in killings of his wife and unborn son. He was arrested after their remains washed ashore in San Francisco Bay in April, near where he said he was fishing Christmas Eve when his pregnant wife vanished.
Prosecutors have said officers mistakenly listened to snippets of two of 69 conversations between Peterson and lawyer Kirk McAllister and one conversation with a private investigator, but Geragos said that was enough to find that they had violated attorney-client privilege.
Girolami has scheduled a June 26 hearing on the wiretap and other matters.
Both sides are bound by a gag order and cannot comment.
In a related court matter, the defense appealed a judge's order to unseal search warrants, saying their release would ignite a "media firestorm of misinformation."
Geragos filed his appeal Tuesday at the Fifth District Court of Appeals in Fresno to keep eight search warrants from being made public next month.
Superior Court Judge Roger Beauchesne ruled Thursday that the documents, which are expected to contain evidence and police theories, should be unsealed July 8 after a previous appellate ruling expires.
That order, however, is now on hold as the court considers Geragos' latest appeal. Prosecutors and lawyers for California newspapers and broadcasters, who argued to release the documents, have a week to file responses.
Police used the search warrants to seize Peterson's truck, boat and trailer, along with scores of items from the couple's home.
Geragos said in court papers that he wants Beauchesne's decision reversed and wants him removed from the case. He maintained that prosecutors told him they, too, want Beauchesne removed from the case, but prosecutors refused to comment, saying they would file their own court papers.