Watching FBI agent Peter Strzok battle with Congress, my initial reaction was pure anger. His repeated, arrogant insistence that he had done nothing wrong despite tons of evidence to the contrary convinced me he deserved immediate firing — if not the firing squad.

Gradually, though, anger gave way to amazement as Strzok grew increasingly combative and condescending. Given his predicament, the sneering and smirking were stupid, and yet he persisted.

Who is this jerk, I wondered, and how in the hell did he get to be a big shot at the FBI? And why are taxpayers still paying for the privilege of his malignant presence on the FBI payroll?

My answers can be summarized in four names: James Comey, Jeff Sessions, Rod Rosenstein and Christopher Wray. They are chief culprits in the death of public trust in the Department of Justice.

The cause of death was murder, and it was an inside job.

Strzok, whose voluminous texts with his office lover show him to be a king of partisan bias, rose to leadership positions under former FBI Director Comey — and it shows. Comey’s self-righteousness was his ultimate undoing, but not before he led the agency into a double death grip of corruption and rank partisanship.

Blinded by his own ambition, Comey brushed aside superiors, rules and maybe laws while giving Hillary Clinton a free pass and turning the screws on Donald Trump. Comey defends himself by saying he sought to protect the FBI’s independence, as if it — and he — are a fourth branch of government that is beyond accountability from the other three.

In the end, he disgraced the agency and himself, though he gained consolation in the millions he made by selling his book to Trump haters.

But the FBI didn’t stink only from the head — Comey’s deputy, Andrew McCabe, also was fired, and could be prosecuted for allegedly being dishonest with investigators about a media leak.

Strzok appears to be a chip off the Comey/McCabe block. Like them, he insists he is committed to the FBI’s high standards, but his reprehensible conduct makes a mockery of his claims.

His stated contempt for Trump and his promise to stop him from becoming president render Strzok unfit to be a dogcatcher.

But, aping his mentors, he nonetheless demands his denials of wrongdoing be accepted as if his integrity is self-evident. All three believe they are entitled to trust and respect, without having to earn or return either.

Which brings us to Sessions, Rosenstein and Wray. How can they stomach the likes of Strzok and refuse to clean the stables?

Sessions, as attorney general, is nominally the boss over his deputy, Rosenstein, and FBI Director Wray. But by recusing himself from anything related to the 2016 campaign, Sessions abdicated the most important part of his job.

As I have said, his appointment was Trump’s biggest mistake, one that denied the president and the nation a functioning attorney general. The most critical result is the unchecked and apparently endless investigation by special counsel Robert Mueller.

Speaking of which, breathes there a soul who believes the timing of Mueller’s latest batch of ghost indictments of Russians has nothing to do with Trump’s planned meeting with Vladimir Putin? The timing shows Rosenstein, who announced the charges, and Mueller are neck deep in politics by trying to force Trump to confront Putin about the meddling charges.

Is that their job? Would they embarrass and try to box in Barack Obama or any other president?

Their decision persuades me both harbor suspicion of Trump’s legitimacy, and thus feel entitled to abuse their powers to wade into issues that are none of their business. In that way, they are no better than Comey, McCabe and Strzok — applying a double standard of law enforcement based on their personal views. That makes them, at the least, allies of the resistance.

Rosenstein’s stonewalling conduct toward Congress over Russia-probe documents is especially suspicious. Claims he threatened members and their staffs ring true, and, if they are, it means he lied under oath when he denied making any threats.

But, thanks to the somnolent Sessions, we can add Rosenstein to the long list of those above accountability. A real attorney general — oh, what’s the use? Sessions is not a real attorney general and never will be.

Then there is Comey’s successor, Wray. He looks as if he wandered into the wrong movie theater and can’t find the exit.

He defined himself as unwilling to tackle the mess he inherited by downplaying the devastating inspector general report on the handling of the Clinton investigation. While conceding the findings made it “clear we’ve got some work to do,” he minimized them by saying, “It’s focused on a specific set of events back in 2016, and a small number of FBI employees connected with those events. Nothing in the report impugns the integrity of our workforce as a whole, or the FBI as an institution.”

Baloney. While it’s true only a fraction of the total employees were singled out, they were the director of the FBI, his top deputy, the deputy’s top lawyer and Strzok, the head of counterintelligence.

Others were also faulted, but not named, including an agent who tried to get his son a job on Clinton’s campaign while sending campaign boss John Podesta “heads up” emails.

And so the corruption of the Justice Department proceeds, unmolested by actual justice. The voter revolution of 2016 has more work to do.

In up to his wa$te

Gov. Andrew Cuomo is a slow learner. Despite two massive corruption cases growing out of his economic development boondoggles, the governor continues to act as if he knows the secret sauce for revitalizing local economies across the state. And reflecting his re-election campaign, he’s inflating the rhetoric.

Cuomo’s office recently sent a flurry of press releases announcing “transformational projects” and taxpayer-funded developments. Batavia, Cortland, Hudson, Hicksville, Rome, Kingston and even the South Bronx got his magic wand waved over their problems.

If past is prologue, scammers, especially Cuomo confidants and big donors, will reap the benefits, followed by investigations, indictments and convictions.

Can’t he just stop?

Blas schooled

Comes now another sign that Brooklyn Borough President Eric Adams is waking up to Mayor Bill de Blasio’s education shell games.

Following a lawsuit, City Hall reneged on a plan to allow a Success Academy middle school to occupy the same space one of its elementary schools used, leaving students and families in limbo. Adams, a Democrat, met with parents and blasted City Hall for making the “situation worse.”

Earlier, Adams initially supported de Blasio’s attempt to end the specialized high school test. But after meeting with Asian parents angered over the plan, Adams withdrew his support.

Speak up, parents. Finally, somebody is listening.

Discounted space

A report says Amazon’s Jeff Bezos might charge $200,000 per person for his planned space tourist flights.

Do Prime members get a discount?