Tyco International’s former chief executive, L. Dennis Kozlowski, took the witness stand yesterday, reversing the strategy he used during his first prosecution for fraud, which ended in a mistrial.

“I never intended to commit any crime at all,” Mr. Kozlowski said in New York state court. “I never conspired with anyone at Tyco to commit a crime.”

Mr. Kozlowski, 58, and his former finance chief, Mark Swartz, 44, are accused of awarding themselves and other executives $150 million in cash,Tyco shares, and loan forgiveness without proper authorization from the board. They are accused of securities fraud for hiding the company’s condition from investors while selling $575 million in shares and options at inflated prices.

The former chief executive, who didn’t testify at his first trial, will now be subject to cross-examination by prosecutors. Mr. Swartz’s decision to testify at the last trial backfired, jurors said, persuading many who were undecided to vote to convict him. Mr. Swartz’s lawyers haven’t said whether their client will testify.

The decision to put a client on the stand is often the most critical defense decision during a trial.

Jurors in the prosecutions of ex-WorldCom Chief Executive Officer Bernard Ebbers and ex-Credit Suisse First Boston banker Frank Quattrone said both men shouldn’t have taken the witness stand. Both were convicted.

Homemaking entrepreneur Martha Stewart didn’t take the stand during her 2004 obstruction trial. She was convicted, too.

Stewart’s lawyer, Robert Morvillo, said Mr. Kozlowski didn’t have much choice but to testify.

“Since the strategy of defending the case by not having him testify pretty much failed, the notion that he changes strategy is not in any way, shape, or form a big surprise,” Mr. Morvillo said.

White-collar defense lawyer Robert Mintz said Mr. Kozlowski’s decision has made the trial “a referendum on his credibility.”

Jurors at Mr. Kozlowski’s first trial, which ended last April, said they were 11 to 1 in favor of conviction when New York State Supreme Court Justice Michael Obus, who presides over this trial, declared a mistrial after the holdout juror reported receiving a threat.

Yesterday, outside the courthouse, Mr. Kozlowski said he “thought it was time” to testify. The holdout juror from the first trial, Ruth Jordan of Manhattan, attended yesterday’s proceedings.

Mr. Kozlowski presided over more than $64 billion of acquisitions in the last five years of his decade as Tyco chief executive. The Bermuda-based company, which operates out of West Windsor, N.J., is the world’s biggest maker of electronic connectors, indus trial valves, and security systems.

Messrs. Swartz and Kozlowski face 31 charges of stock fraud, falsifying business records, grand larceny, and conspiracy. The most serious charge carries a 25-year jail term. Both men are free on bond.

Prosecutors claim in court papers that Messrs. Kozlowski and Swartz abused company loan programs to live “like royalty.” Mr. Kozlowski used money borrowed from Tyco relocation and tax-loan programs for paintings, property, jewelry, and parties.

Messrs. Kozlowski and Swartz claim their actions were proper and that they made no attempt to hide their activities from Tyco’s board or auditors. Prosecutors say the two carefully omitted reference to the bonuses and borrowings from documents reviewed by directors and shareholders or sought approval after the fact.

Yesterday, defense lawyer Stephen Kaufman asked Mr. Kozlowski about $25 million in company loan forgiveness he received in 1999. Mr. Kozlowski said he couldn’t explain why the payment didn’t appear on the income statement he filed with his tax return that year.

“I was just not thinking when I signed my tax return that I had a loan forgiven,” he said. “It just got confusing.”

Mr. Kozlowski said the loan forgiveness was arranged with Tyco director Phil Hampton. “I asked Phil whether I needed to do anything else on this,” Mr. Kozlowski testified. “He said not at the time.” Other directors have testified that they were never informed of the loan forgiveness. Hampton died in 2001.

Mr. Kozlowski said two other bonuses totaling $48 million, awarded in 2000, were also arranged through Hampton, then-chairman of Tyco’s compensation committee. Mr. Swartz received bonuses in 1999 and 2000 under the same circumstances.

Prosecutors said Messrs. Kozlowski and Swartz abused Tyco’s Key Employee Loan Program to buy jewelry, real estate, and fine art. Mr. Kozlowski conceded that he and other executives used the plan to buy houses and boats, but that he wasn’t required to state the purpose of the loan.

Mr. Kozlowski is accused of paying an unauthorized $20 million finder’s fee to director Frank Walsh for helping arrange an acquisition in 2001. Mr. Walsh testified earlier that Kozlowski had asked him not to disclose the fee arrangement.

Yesterday, Mr. Kozlowski said he only asked Mr. Walsh not to mention the arrangement to other investment bankers. Mr. Kozlowski said he told Tyco’s board that he believed the fee was proper and offered to step down as CEO if they disagreed. He said they didn’t.

“Did you believe the board had authorized the fee?” Mr. Kaufman asked. “Yes, I did,” Mr. Kozlowski said.