L Dennis Kozlowski and Mark H Swartz won a reprieve of sorts yesterday when the judge presiding over their trial declared a mistrial due to pressure brought to bear on one juror. The case is certain to be retried.

Even before Mark H. Swartz was indicted along with the former Tyco chief executive L. Dennis Kozlowski, the names of the two men were already linked in analysts’ reports and news articles.

Mr. Kozlowski was the flamboyant leader, and Mr. Swartz was the solid and loyal chief financial officer.

Their business and personal lives were so intertwined that when Mr. Kozlowski created a trust in 1997 to buy a $5 million house on Nantucket, he named Mr. Swartz as trustee.

Yesterday’s events make it difficult to gauge just how effective either side’s arguments were – whether the prosecution’s evidence of Mr. Swartz’s and Mr. Kozlowski’s opulent tastes was persuasive, for example, or whether the defense team could have carried the day with its arguments that all their spending was aboveboard.

News articles over the years about Tyco described the two men as doing similar things.

When Mr. Kozlowski sold $70 million in shares back to Tyco in 2000 and 2001, Mr. Swartz sold back $35 million. Both men sold even though they said publicly that they were holding onto their stock.

Later, after various publications wrote about the sales, which were disclosed in regulatory filings in early 2002, both promptly pledged to buy new shares in the company.

As Mr. Kozlowski led Tyco on an acquisition spree, it was Mr. Swartz who handled the conference calls and defended accounting for transactions that some analysts and investors at the time criticized as opaque.

Investigators later said that the bookkeeping helped the company seem to be growing rapidly – and deserve its lofty stock price – when in fact its performance was lackluster.

Together, the men have fought criminal charges in a trial that lasted six months. But of the two executives, only Mr. Swartz – appearing relaxed and even content during the trial – testified in court.

So calmly did Mr. Swartz conduct himself while testifying in February that one prosecutor, Ann Donnelly, warned jurors not to trust him.

“Mark Swartz has truly mastered the art of communication,” she told jurors during her closing statement. “He makes eye contact, he actually cares about you like he’s really listening to the question – at times it was almost like watching somebody on a talk show.”

Defending himself against criminal charges has represented a steep fall for Mr. Swartz, who came to Tyco in 1991 from the accounting firm Deloitte & Touche, where he was a consultant.

According to a glowing article about Mr. Swartz in CFO Magazine in 2000, Mr. Kozlowski hired Mr. Swartz to help build a team to handle acquisitions.

Mr. Swartz, who was named Tyco’s chief financial officer in 1995, oversaw its finances, taxes, information systems, administrative offices and human resources.

He also considered the merits of hundreds of Tyco acquisitions, which helped to transform a New Hampshire-based manufacturer with 23,000 employees in 1992 into a behemoth with 240,000 employees by 2002.