Eric Jackson arrived in Dallas in March 2017 as the FBI's special agent in charge, promising that his office would aggressively pursue public officials who abuse their positions.

Two years later he is leaving, but not before compiling a list of Dallas public officials who are now facing prison time.

And the FBI did it without having to take anyone to trial.

"We can't have the public lose their trust in their elected officials," said Jackson, on the eve of his retirement to take a job in the private sector.

That retirement didn't come fast enough for four prominent public officials in Dallas who – thanks to the FBI – have pleaded guilty to federal corruption charges.

The FBI's success, under Jackson's watch, also includes catching two businessmen who ultimately pleaded guilty to paying, or directing, bribes to government officeholders.

"The city of Dallas, the citizens of Dallas, they deserve better," Jackson said.

Last Friday, he announced that a former Dallas City Council member, while head of a powerful public housing committee, pleaded guilty to federal charges of taking bribes from a developer.

In another FBI case under Jackson, Dallas' mayor pro tem pleaded guilty to taking bribes totaling more than $400,000, despite telling NBC 5 Investigates in an earlier interview that he would never do such a thing.

Jackson's office also investigated a school busing superintendent who later pleaded guilty to taking an estimated $3 million in bribes and kickbacks – money used for, among other things, fancy cars and a vacation pad in New Orleans.

That plea came after NBC 5 Investigates began questioning the superintendent's use of taxpayer dollars.

Jackson praised his agents for doing their work in a "quiet …professional manner," convincing those who have committed wrongs to waive their right to a trial and, instead, plead guilty.

He arrived in Dallas just as the federal corruption case was wrapping up against Dallas County Commissioner John Wiley Price, who ultimately was acquitted, ending a court fight that had lingered for years.

At that time, Jackson told NBC 5 Investigates he would not be deterred by the government's defeat in the Price case.

"We respect the jury's verdict," he said at the time, "but that doesn't change the responsibility that we have to ensure that those individuals who are in a position of trust are doing what they are supposed to do."

As he prepared to retire, Jackson declined to say where he leaves the FBI's investigation of Dallas County Schools, the case that toppled the school bus agency, it's superintendent, the mayor pro tem and the New Orleans businessmen who enticed them with bribes. Jackson said he could not comment on whether any additional charges are expected against others.

He is leaving the FBI to become a corporate security manager, but declined to be more specific other than to say he will remain in Dallas, his hometown.

"Yes, staying here most definitely. This is home," he said.