(Bloomberg) ? The mistrial in the case of former Tyco International Ltd. chief executive officer L. Dennis Kozlowski and his top lieutenant Mark Swartz is the second defeat for white-collar crime prosecutors in five months.

The trial of ex-Credit Suisse First Boston investment banker Frank Quattrone ended in a mistrial in October after jurors couldn?t agree on a verdict in his obstruction of justice case.

High profile trials that put massive media attention on jurors increase the potential for mistrials, jury deadlocks and misconduct within the panel, former prosecutors said.

?Whenever you inject the element of the press and public attention into a case, you create the possibility of greater juror and outside factors influencing the jury,? Kirby Behre, a former federal prosecutor now in private practice in Washington, said. Friday?s mistrial in the Tyco case was the result of outside pressure on a juror, said Manhattan state Supreme Court Justice Michael Obus. Defence lawyers told him a juror had been subjected to external pressure. The Associated Press, quoting an unnamed source, reported that the juror had received a threatening letter. The panel had been deliberating for 12 days.

?Here we have a very striking example of somebody writing to a juror,? Behre said. ?Obviously that would not happen if this were some anonymous case.?

Alleged juror misconduct is behind a request by homemaking entrepreneur Martha Stewart for a new trial. Lawyers for the founder of Martha Stewart Living Omnimedia Inc. filed a motion for a new trial Wednesday citing alleged lies by a juror about his arrest record.

?The greater the press attention, the greater the temptation to seek a position on a jury because you want your 15 minutes of fame,? Behre said.

Obus referred specifically to Juror No. 4, who has been the centre of news media attention since last week when the panel indicated that one of its members was convinced the prosecution had failed to prove its case and was refusing to deliberate in good faith. Some courtroom observers said the juror, a 79-year- old retired schoolteacher with a law degree, made an ?OK? gesture last Friday that appeared to be a favourable signal to the defence.