An executive at Donald Trump's company testified that he was afraid he'd hear those famous words — "you're fired!" — if he went to the big boss with concerns that two top company officials were scheming to dodge taxes on company-paid perks.

Senior Vice President and Controller Jeffrey McConney told jurors at the Trump Organization's criminal tax fraud trial that he didn't see much upside if he ratted on longtime finance chief Allen Weisselberg or operations chief Matthew Calamari Sr., two of Trump's most trusted, loyal lieutenants.

"I thought if I started refusing or fighting back, I'd probably lose my job," McConney said near the end of a sometimes contentious fourth day of testimony, a lengthy warm-up act for Weisselberg's looming turn as the prosecution's star witness.

"Allen was my boss. Who was I going to tell? I wasn't going to confront him with it. I wasn't going to argue," McConney said at another point in his testimony. "I was going to do what he told me to do."

Judge Juan Manuel Merchan declared McConney a hostile witness after prosecutors complained that he had been far more responsive to defense questioning, even though he was granted immunity to testify as a prosecution witness.

McConney, who still works for the Trump Organization and has a company-paid lawyer, acknowledged on the witness stand Monday that he's been speaking with company lawyers about his testimony when court wasn't in session. He said he even performed some tax calculations on their behalf Sunday night.

"I think it is pretty clear to the average observer, he is very helpful to you [the defense]," Merchan said. "On the other hand, it seems like he has a really hard time understanding the people's questions and he has a hard time, frankly, giving credible answers."

McConney is scheduled to return to the witness stand on Tuesday. As a hostile witness, he could be subject to several more hours of questioning as prosecutors seek to square his previous trial testimony and his answers to questions during eight grand jury appearances in the last few years.

The Trump Organization, the holding company for the former president's various assets, including buildings, golf courses and hotels, is accused of helping some top executives avoid income taxes on compensation they got in addition to their salaries.

The company, which could be fined more than $1 million if convicted, has denied wrongdoing. Its lawyers allege that Weisselberg concocted the scheme on his own, without Trump or the Trump family's knowledge, and that the company didn't benefit from his actions.

Weisselberg, 75, has pleaded guilty to taking $1.7 million in off-the-books compensation and agreed to testify as a prosecution witness at the trial, possibly as early as Tuesday, in exchange for a five-month jail sentence.

Trump Organization lawyer Susan Necheles turned part of McConney's cross-examination into a preemptively attack on Weisselberg, eliciting testimony that he sneakily tried to enrich himself on the company's dime.

McConney said Weisselberg and Calamari Sr. leaned on him over the years to fudge payroll records to hide extras such as Manhattan apartments and Mercedes-Benz cars from their taxable income, in part by reducing their salaries by the cost of those perks and issuing falsified W-2 forms.

McConney said Weisselberg, his supervisor, once even had him set his wife up with a one-time $6,000 payroll check for a no-show job at the company so she could qualify for Social Security benefits. He said Weisselberg warned him not to tell others in the company about what they were doing.

"Allen Weisselberg did not want other people at the company to know this secret," McConney said.

Trump signed off on some salary adjustments, which McConney said Weisselberg claimed was his way of paying back the company for the perks, but it isn't clear if he knew they weren't paying taxes.

Neither Trump nor any of his children who have worked as Trump Organization executives are charged or accused of wrongdoing.

Prosecutor Joshua Steinglass seized on McConney's reluctance to tell Trump, questioning him on what's known as re-direct examination, a chance for him to ask more questions after the defense's cross-examination.

"You falsified W-2s, you invented an employee and gave her a W-2 for work she didn't perform," Steinglass asked. "Did you ever bring this to Donald Trump's attention and say, 'the CFO is making me commit a fraud. … I'm uncomfortable doing this.'"

"No," McConney said.

Also Monday, the judge in the New York attorney general's fraud lawsuit against Trump and the Trump Organization has appointed former Manhattan federal judge Barbara Jones as an independent monitor overseeing the company's business dealings.

Jones recently served as special master in two other high-profile cases related to Trump. She reviewed materials seized in FBI raids on Trump's onetime personal lawyers — Michael Cohen, in an investigation related to hush-money payments, and Rudy Giuliani, in a probe of his dealings in Ukraine.

Michael R. Sisak reports for the Associated Press.

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