Jim Walden went after the mob as a federal prosecutor. Now he’s investigating N.J. tax breaks.

As a Temple University law student, Jim Walden loved the bankruptcy code so much that he mapped it out on 30 pieces of paper he taped together, so he could understand each part.

Later, as a federal prosecutor, going after organized crime and heroin traffickers, Walden picked up a Drug Enforcement Administration analyst’s trick of making timelines as he worked a case. Creating chronologies out of emails, text messages, and meetings became a habit – to the point that one chart he made stretched the length of a conference room table.

Now, as Walden and a team of investigators are digging into the intricacies of New Jersey’s multibillion-dollar tax-break programs for businesses, he declines to say whether the timeline skills are coming in handy, but allows that “diligence pays off” in complex cases.

“Think about what we know. There was a new piece of legislation that essentially created an uncapped pool of money for the [Economic Development Authority] to administer – for the first time in the history of New Jersey,” Walden said earlier this month. “That was the moment for someone to have the lightbulb go on: to say, ‘Wait a second, we really need to devise an intelligent program to make sure that we’re vetting, double-checking, confirming, and protecting against misuse of this program.’ And that just didn’t happen.”

After his early mob work, Walden, 53 and a Levittown native, branched out. His clients have ranged from a whistle-blower on widespread doping by Olympic athletes in Russia, to a former AIG insurance executive, and public housing residents fighting for lead inspections.

His latest case, in the Garden State, has him examining the unprecedented tax-credit program, which was revamped by the 2013 Economic Opportunity Act – and tangling with one of the state’s preeminent political power brokers, George E. Norcross III.

The task force, established by Gov. Phil Murphy in January and chaired by Rutgers law professor Ronald Chen, has already identified $500 million in tax breaks that could be rescinded. It has referred evidence of “unregistered lobbying” to law enforcement, and documented the behind-the-scenes changes that a powerful law firm wrote into the tax-credit legislation in 2013.

The investigation, and Walden’s role as special counsel, specifically, has earned the ire of Norcross, whose insurance brokerage and business associates have come under scrutiny. Last month, Norcross and several firms sued Murphy, claiming the task force was created unlawfully. They named Walden as a defendant, too.

Walden is now in the middle of a nasty political fight in Trenton that shows no signs of abating. His inquiry comes as the governor and lawmakers debate whether and how to retool the state’s economic development programs, which are set to expire July 1.

READ MORE: ‘Permanent’ damage? N.J. Democrats gripped by George Norcross-Phil Murphy feud over tax credits.

“There’ve been a couple twists and turns,” Walden said one afternoon in his Lower Manhattan office, lined with family photos and Phillies memorabilia – including a bobblehead of Mike Schmidt, a Robin Roberts magazine cover, baseballs signed by Pete Rose – and offering sweeping views of the Hudson.

It was a few days before a judge ruled in the governor’s favor on a key motion, allowing investigators to publish their initial findings. The report, released within minutes of the ruling, questioned tens of millions of dollars in awards to Norcross’ insurance brokerage, and to his partners in a new office tower in Camden.

The companies have vigorously denied any wrongdoing. Norcross has cast the investigation as a politically motivated attack. In a recent legal filing, his lawyers argued the public hearings held by the task force are one-sided “show trials.”

“On George Norcross, all I can say is, I didn’t know the name before I started this project,” Walden said. “Our investigation is about the EDA and in an ancillary way, to identify whether certain companies got one past the EDA, from the perspective of, should the EDA have asked more questions.”

Companies, he continued, may have “innocent explanations for whatever red flags we find. But we’re not going to be deterred in our work.”

Four years ago, after stints at the Big Law firms O’Melveny & Myers and Gibson Dunn & Crutcher, Walden founded his own boutique litigation firm. He is charging New Jersey a discounted rate, $395 an hour, for the investigation. The firm has billed the state $3.2 million to date.

Back in Levittown, the idea that Walden would go to college wasn’t a given. Money was a struggle in his household, and he recalled that less than 10 percent of his senior class at Harry S Truman High School went on to any form of higher education. After he graduated, Walden worked for a year, and with a friend’s encouragement, applied to Hamilton College, and got accepted with financial aid.

The affordability of in-state tuition brought him to Temple Law – which he speaks of in glowing terms – and Walden later landed a clerkship with U.S. Appeals Court Judge Anthony Scirica in Philadelphia. He helped steer Walden toward becoming a prosecutor, despite Walden’s avid interest in bankruptcy law.

One day, Scirica, who still sits on the bench, asked Walden to observe a murder and racketeering trial, and report back on the experience. Watching closing arguments, as a prosecutor pointed to a defendant who she said pulled the trigger, “the hairs on the back of my neck stood up.” He decided to apply to the U.S. Attorney’s Office, and got a job with the Eastern District of New York in 1993.

As a young prosecutor, Walden was eager to make big cases, and an FBI agent put him onto a string of bank robberies, being carried out by a loose collection of mob associates. Walden started working the cases one by one, leading to takedowns of major players, including a prominent member of the Bonanno crime family. By the time he left the Eastern District in 2002, the office had prosecuted hundreds of people connected to the mob as a result of his work.

In private practice, Walden has developed a niche working on what he calls “good government” litigation – essentially getting the government to look in the mirror, and do a better job.

The EDA inquiry, he said, combines that approach with a more traditional white-collar investigation.

While Walden says “there are a lot of good people at the EDA,” he also emphasizes that the agency was “on notice” of problems, because of a whistle-blower suit that contained allegations about tax-credit applications. The fact that the agency did not disclose the pending lawsuit to the state comptroller during an audit, “to me, says everything you need to know about the problems at the EDA,” Walden said. “It’s just inexcusable.”

The first “good government” case he worked on involved thousands of New Yorkers who had lost their food stamps because of a computer failure that the city knew about, and didn’t fix. In the public housing case he brought, a New York federal judge ordered lead inspections inside apartments. And in an anti-bullying case, against the city’s Department of Education, the agency agreed to adopt new policies to deter violence.

He has gravitated to that type of work, in part because of his upbringing. His dad was a truck dispatcher for a company that serviced U.S. Steel’s Fairless Works, and he was laid off when Walden was around 12. “I will never forget the feeling of going into the unemployment office with my dad,” he said. “I remember to this day, not a good feeling obviously when you’re a kid. So, I’ve been there.”

And he was galled by the arrogance he saw in the food-stamp case, and others. “Government agencies … were doing things that were patently illegal, at the same time the government judges other people for doing bad things,” Walden said. “It just seemed like such a hypocritical double standard.”

Walden knew Big Law firms were reluctant to sue city agencies precisely because “if it turns out bad, there are important people in the administration that partners probably know.”

But he has not shied away from cases with the potential to metastasize politically. The public housing case drew in familiar foes, New York City Mayor Bill de Blasio and New York Gov. Andrew Cuomo. And now, he’s playing a key role in the EDA investigation, which has led to new levels of tension in Trenton between Murphy and Norcross allies in the Legislature.

Walden, however, stresses an above-the-fray approach to his work. He’s been an unaffiliated voter since leaving the Democratic Party in 2006, and says he mistrusts both parties.

“More to the point, I’m no one’s shill,” he said. “I’ve had clients – I can’t really tell this story – but I certainly have had more than one public client – public official client – direct me to do something that I did not think was the right thing to do, and I told them to pound sand.”

Amid the investigation, the lawsuit, and the politicking of Trenton, developments on the tax-incentive front have moved at a breathless pace, seemingly in tandem some days. The task force is scheduled to hold its next public hearing July 9 in Trenton. And it has issued a round of administrative subpoenas to several organizations with ties to Norcross, whose legal team has challenged the subpoenas in court.

“The companies have repeatedly said there is another side to the story,” Walden said in a follow-up call, by way of explaining why the subpoenas were issued. “We want to get all the facts.”