"Did you commit crimes with Mr. Manafort?" a prosecutor asked Gates.
Gates is cooperating with the investigation as part of a plea bargain with the prosecution, whilst Paul Manafort denies all charges- which include tax fraud; bank fraud; and failing to report foreign bank accounts. He said he engaged in the wrongdoing at Manafort's direction.
Gates also told jurors that he cheated Manafort out of "several hundred thousand" dollars, which is likely to be a threat Manafort's attorneys pull on to try to undermine Gates' credibility with the jury.
Throughout his testimony, Gates largely avoided making eye contact with Manafort, who appeared to be watching him.
Manafort has pleaded not guilty to 18 counts of bank and tax fraud and failing to disclose foreign bank accounts.
If someone has foreign bank accounts, companies, or interests, that person often must disclose those interests in FBARs to the Treasury Department in addition to their tax returns.
The criminal case has nothing to do with either man's work for the Trump campaign and there's been no discussion during the trial about whether the Trump campaign coordinated with Russian Federation - the central question Mueller's team has tried to answer. But Gates pleaded guilty months later and agreed to co-operate in Mueller's investigation of Manafort, the only American charged by the special counsel to opt for trial instead of a guilty plea.
Prosecutors say Manafort did lucrative political consulting work in Ukraine, and then kept much of the money he made in offshore accounts and companies.
Manafort, a veteran lobbyist, has tried to get the financial charges against him dismissed and arguing that Mr Mueller has a "blank check" that he "has cashed, repeatedly".
Gates began working for Manafort in 2006 on his business ventures in Ukraine.
German couple JAILED for raping son and selling him to paedophiles
A Spanish man was on Monday (Aug 6) sentenced by the court to 10 years behind bars for repeatedly sexually abusing the young boy. The Freiburg state court ruled that the 39-year-old man must remain in preventive custody after serving his sentence.
Salon staff beat customer with brooms after she refuses to pay
The incident has inflamed racial tensions, and prompted calls for black residents to spend their money elsewhere. Officers had gone to the salon to arrest a second employee, but that worker was not there at the time.
Once-eased U.S. economic sanctions against Iran back in effect
Speaking in a television interview, he also demanded compensation for decades of American "intervention" in the Islamic Republic . Mr Trump warned that those who do not wind down their economic ties to Iran "risk severe consequences".
But Ms Laporta's testimony raised the stakes for Mr Manafort, legal experts said.
Rick Gates dropped a bombshell in his testimony against his former business partner, Paul Manafort, in federal court Monday.
Gates testified that Manafort told him to report overseas income as loans to lower Manafort's taxable income, supporting the testimony of his accountant.
Some of the manoeuvres were at the request of Gates, while others implicated Manafort, Laporta testified.
Whilst the charges against Manafort do not directly relate to Trump's presidential campaign, or any potential collusion, both Gates and Manafort were indicted as a direct effect of Mueller's investigation.
Ms LaPorta told the court on Friday she had suspected Gates was misleading her about Mr Manafort's finances.
Under cross examination on Monday, defence attorney Kevin Downing attempted to show that Gates was the point person in dealing with the accountants.
Andres said he was entitled to show the jury why Manafort was getting tens of millions of dollars in payments.