When Scott Rothstein takes the witness stand Monday for an unusual deposition involving the bankruptcy of his law firm, the convicted con man’s credibility — if he has any — will be in the eye of the beholder.

Dozens of lawyers trying to recover millions for victims of his $1.2 billion investment scam will want to believe Rothstein’s every word if he says he colluded with deep-pocketed parties such as TD Bank, where the disbarred Fort Lauderdale attorney manipulated his clients’ trust accounts.

But lawyers defending the bank and others who might be on the hook for big bucks lost in his massive fraud will paint him as a pathological liar.

“Without exaggeration, every act that Scott Rothstein undertook and every word that he uttered was designed to mislead and deceive everyone around him,” said Miami criminal defense attorney Sam Rabin, who represents a TD Bank vice president, Frank Spinosa, who dealt directly with Rothstein and is under criminal investigation.

Rothstein, now serving a 50-year prison sentence on a racketeering conspiracy conviction, will be questioned by more than 30 lawyers about details of his Ponzi scheme when he sits for the closed-door civil deposition, scheduled to last two weeks. It gets underway Monday amid heavy security in the James Lawrence King Federal Justice Building in downtown Miami.

The disgraced lawyer is serving his prison term in the federal witness protection program and has already spent hundreds of hours spilling his guts to federal authorities. Now the civil lawyers are chomping at the bit to grill him about his Ponzi scheme, the bankruptcy of his now-defunct Fort Lauderdale law firm, Rothstein Rosenfeldt Adler, and related litigation.

In federal court last year, some 320 victims filed claims for losses totaling more than $360 million, mostly stemming from Rothstein’s sale of phony legal settlements to wealthy investors from Florida to New York to Texas.

His fictitious financial empire crumbled in fall 2009 when dozens of investors began clamoring for millions they had invested in the purported employment-discrimination and sexual-harassment settlements.

Rothstein has already been entrenched in South Florida history as a one-man wrecking ball who destroyed his own 70-attorney law firm and used it to play among rich investors, society types, trendy entrepreneurs and prominent politicians — including Gov. Charlie Crist and Republican presidential nominee John McCain.

All of that will be fair game when the bankruptcy trustee Herbert Stettin and his team of lawyers question Rothstein during the civil deposition.

So far, they have managed to recover more than $100 million that Rothstein paid to investors and other creditors. From whatever the bankruptcy lawyers recover, 18 percent will go to them and the rest will be proportionally redistributed to creditors — depending on how much they invested with Rothstein and how much they were paid back before his scheme fell apart.

But Stettin’s work is far from over, which is why Rothstein’s deposition is so crucial.

Just obtaining permission for his deposition was an ordeal, requiring dispensation from U.S. District Judge James Cohn, who is presiding over the criminal case, and the U.S. attorney’s office, which has charged eight defendants including Rothstein so far and plans another major racketeering indictment.