"Were you involved in criminal activity when you worked for Paul Manafort?" federal prosecutor Greg Andres asked the witness.
Speaking at Manafort's trial late that afternoon, Gates bluntly answered the prosecutor's questions.
Attorneys representing Manafort have built their defense argument around Gates, painting him as the true culprit behind their client's alleged crimes and asserting that Manafort's only mistake was "placing his trust in the wrong person", referring to Gates.
Gates is the prosecution's star witness after he cut a plea deal this year and admitted two felony charges.
The warning came after multiple reporters rushed out of the courtroom at the same time Monday after it was announced that Gates would testify Monday.
Red tide, dead fish plague tourists
The city is issuing a daily "fish kill clean-up" report because of the "unprecedented volume of dead sea life now washing up". The sparkling white sand of Florida's southwestern beaches aren't dotted with sunbathers this week.
The judge in the Paul Manafort trial reminded Special Counsel Robert Mueller's team on Friday of the high bar for conviction - that they must prove the former Trump campaign chairman knowingly violated tax and bank laws related to his political work overseas.
Manafort has pleaded not guilty to 18 counts of bank and tax fraud and failing to disclose foreign bank accounts.
The defendant's lawyers say Rick Gates embezzled millions of dollars from Mr Manafort's consulting firm. Laporta, looking at a summary of loans to Manafort and his businesses, said she could not see any indication that the loan from Deripaska had been paid off.
Mr Manafort, 69, could spend the rest of his life in prison if found guilty of all the fraud charges. Manafort attorney Kevin Downing will cross-examine Laporta, who is testifying under an immunity agreement because she feared prosecution for perjury or false statements.
Within moments of taking the stand, Gates - seated just twenty feet from Manafort in the Alexandria, Virginia, courthouse - conceded to jurors that he aided Manafort in committing crimes.
But Manafort's defense team is expected to use Gates, too.