Two audiotape recordings have made the news this week in connection with legal proceedings. Both involve high-profile cases, one on a national level and the other one locally.

The judge in the second-degree murder case of Florida neighborhood watchdog George Zimmerman (who is charged with slaying teenager Trayvon Martin) excluded expert testimony offered by the prosecution deciphering and interpreting an audio recording of a 911 emergency call. Although the judge allowed the jury to hear the recording, she disallowed the analysis on grounds that the techniques used were not "reliable" for purposes of allowing the experts to testify as to whose voice is being heard on the tape screaming for help or the precise wording.

Meanwhile, a surreptitiously made tape-recording of a conversation between Michael Brodkorb, the fired communications chief of the Republican caucus in the Minnesota Senate, was revealed by an ­anonymous source.

The ex-aide, who is in the midst of a contentious and highly costly lawsuit, secretly taped several conversations with a leader of the senate, Michelle Fisch­bach, shortly after he was abruptly fired following disclosure of an intimate affair between him and then-Senate Majority Leader Amy Koch. The recordings, made without ­Fischbach's awareness, reflect her misgivings about Brodkorb's firing, which could come in handy when Brodkorb's case goes to trial next summer.

The two tapes — the confrontation between Martin and Zimmerman, which led to a fatal finale, and the Brodkorb-Fisch­bach one, which followed the discharge decision — raise a number of points about the use of tape recordings in the legal system.

The legal tale of the tape of the Martin-Zimmerman clash, in which Zimmerman asserts he acted in self-defense, turns on the propriety of methodology used by the experts in trying to ascertain who was saying what on the recording. The experts selected by the prosecution came up with a few phrases that others could not hear and also opined that the voice beseeching for assistance was that of the slain youth, which bolsters the prosecution's murder charge.

Expert witness testimony plays a major role in litigation, but before it is admissible, it must be cleared by a judge. Under the general rules of evidence, in most jurisdictions, judges must determine that the testimony to be offered by an expert will "assist" the jury and is based upon "reliable principles and methods" and "generally accepted" by other knowledgeable individuals.

The "reliability" and lack of general acceptance factors doomed the proposed testimony by the prosecution's audio experts in the Florida fracas. Those criteria have been the bone of much controversy in connection with expert witness testimony, dating back at least two decades to a decision in the mid-1990s by the U.S. Supreme Court, written by Justice Harry Blackmun of Minnesota, in which the high court established standards for allowing expert witness testimony in federal court cases. Most of those standards are followed, in varying forms, by state courts as well.

The "reliability" and generally accepted standards are supported by those who seek to avoid "junk" science being introduced into legal proceedings. Others, however, see those criteria as sometimes creating a bar to new, creative or innovative ways to prove cases through the expertise of knowledgeable witnesses. They assert, under a strict application of those criteria, Galileo's revelation that the Earth revolves around the Sun, rather than vice versa, would be cast aside as mere hypothesis for several centuries, as it was, in fact, by religious officials.

Expert analysis of blurred audiotapes has proved to be a dilemma for the legal system for many years. In the late 1970s, a congressional committee concluded that President John F. Kennedy was the victim of an assassination conspiracy, based largely on last-minute testimony of expert witnesses who analyzed a dictation belt that was purportedly on a motorcycle of a police officer who was accompanying the president's limousine through downtown Dallas when he was shot in Nov. 22, 1963. But their testimony, accepted by a majority of the committee, was later disowned by other experts, as well as the Justice Department, which refused to take action on the report. The truth of the Kennedy assassination remains a mystery to many, even approaching the 50th anniversary of the event.

The tapes in the Brodkorb brouhaha raise different legal concerns. Minnesota is one of approximately three dozen states where surreptitious, or secret, tape records, whether in person, telephone or otherwise, can be utilized in legal proceedings, as long as one party to the conversation, usually the party doing the taping, consents to it. In these "one consent" jurisdictions, as long as a person is in the state making the taping, the tape is lawful, regardless of the location of the other parties to the recording.

In some 13 other jurisdictions, the law restricts secret taping done without the consent of all participants. In some states, the illegal recording can be a crime, even a felony, while in others, the restrictions are more ambiguous. For instance, in Maryland, where Linda Tripp taped some of her conversations with Monica Lewinsky, which underlied the impeachment imbroglio of President Bill Clinton, secret taping is illegal if the party doing the taping knows about the illegality, a matter that the authorities could not prove in Tripp's subsequent trial.

The use of secret taping has increased because of its permissibility in Minnesota and most other states, along with the development of unobtrusive devices to do the taping, compared to the body wires and other paraphernalia that characterize the old gangster-­informant movies. Their easy deployment and utilization in legal proceedings should caution individuals to be wary of what they say and how they say it, lest their remarks rebound against them in subsequent legal proceedings.

How these two cases, one criminal and one civil, will turn out remains to be seen, but regardless of the outcomes, they will leave a lasting legacy for audiotaping of controversial incidents.

------------------

Marshall H. Tanick is a Minneapolis attorney.