FORT LAUDERDALE, United States (Reuters) – A former top banker who headed global wealth management at UBS AG was found not guilty on Monday on US charges of conspiring with wealthy Americans to hide US$20 billion in secret offshore accounts.

Raoul Weil, the highest-ranking Swiss banker to stand trial in the United States, was accused in South Florida federal court of conspiracy to defraud the Internal Revenue Service.

The verdict was a major setback to the US Justice Department which spent six years seeking to prosecute Weil, including extraditing him from Italy last year.

The jury took only 75 minutes to reach its verdict after a three-week trial that ended abruptly on Monday when Weil’s defence team decided not to call any witnesses, saying the government had failed to make its case.

The defence team jumped up in joy as the verdict was read. Weil, 54, held his sobbing wife in a lengthy embrace.

“The jury sent a strong message to the government. This case should never have been brought,” said Weil’s lawyer, Matthew Menchel.

Weil declined to comment upon leaving the courthouse.

Legal experts said that while the government presented plenty of evidence that bankers at UBS defrauded the IRS, including some who testified at the trial, it failed to show that Weil was intimately involved in those schemes.

“For a jury to acquit after only an hour means that there were some huge holes in the government’s case,” said David Weinstein, a former federal prosecutor now in private practice in Miami.

In a defence motion for acquittal filed last week, the defence argued that the government offered no evidence “to show that Mr Weil ever knowingly agreed with any US client to defraud IRS”.

Instead, the defence said the while government presented evidence of wrongdoing by UBS bankers, it focused most of its case “on witnesses who offered testimony of misconduct that was never connected to Mr Weil”.

Weil was arrested in October 2013 while on vacation with his wife at an upscale hotel in the northern Italian city of Bologna. He pleaded not guilty last year after being extradited to the United States.

The trial pitted Weil against several former UBS colleagues who chose to cooperate with US authorities in exchange for favourable sentencing.

They testified about using numerous James Bond-like tactics to avoid detection while in the United States, and to help US clients keep their accounts hidden from tax authorities.

During his closing argument, Menchel said the prosecution’s case rested on the testimony of ex-employees of UBS who were more guilty of crimes than Weil.

“Who are the real criminals here?” Menchel said. “Who should be getting punished instead of getting sweetheart deals?”

Assistant US Attorney Jason Poole told the jury that Weil knew what he was doing was wrong and orchestrated efforts by UBS to circumvent US tax law.