If Donald Trump wants to be a serious candidate for president, we deserve to know more about his business with mass murderers whose plunder of public and private funds added up to billions.

Donald Trump is running for president. Many believed or hoped that the Donald’s latest foray into national politics was nothing more than a public-relations move, not a serious attempt to reside at 1600 Pennsylvania Avenue.

But now that Trump holds the lead in national polls, as well as polls in Iowa and New Hampshire, it’s time to take his campaign seriously. Media outlets like Huffington Post and the Wall Street Journal, which are covering Trump’s run as an entertainment story, not a news story, are making a mistake. If Trump wants to be a serious candidate for president, and has the numbers to back it up, he must be vetted like a serious candidate for president. A good place to start is to take a hard look at Trump’s ties to Philadelphia and New York organized-crime families.

Donald Trump’s Connections to Organized Crime

Trump was building his eponymous empire of hotels, casinos, and high rises in the early 1980s in New York City and Atlantic City. In both places, the construction industry was firmly under the thumb of the mafia. And in both places there are literally concrete connections between La Cosa Nostra and Trump’s lavish projects. Pulitzer Prize-winning journalist David Cay Johnston, who has covered Trump for decades, has written a very useful list of questions for Trump. Many focus on his ties to the mob. In addition in his 1992 book, “Trump, The Deals and the Downfall,” author Wayne Barrett lays out a slew of suspicious dealings and associations.

The Atlantic City story starts with Trump’s purchase of a bar, at twice its market value, from Salvatore Testa, a made man in the Philadelphia mafia and son of Philip “Chicken Man” Testa, who was briefly head of the Philly mob after Angelo Bruno’s 1980 killing. Harrah’s casino, half owned by Trump, would be built on that land, and Trump would quickly buy out his partner, Harrah’s Entertainment, and rename the casino Trump Plaza.

Author Wayne Barrett lays out a slew of suspicious dealings and associations.

Trump Plaza’s connection to the mob didn’t end with the land purchase from Testa. Nicademo “Little Nicky” Scarfo (who became boss after the elder Testa was blown up) and his nephew Phillip “crazy Phil” Leonetti controlled two of the major construction and concrete companies in Atlantic City. Both companies, Scarf, Inc. and Nat Nat, did work on the construction of Harrah’s, according the State of New Jersey Commission of Investigation’s 1986 report on organized crime. In addition, Scarfo, whose reign as head of the Philly mob was one of the bloodiest in history, controlled the bartenders union, which represented Trump’s workers in Atlantic City, according to George Anastasia’s book, “Blood and Honor.”

One more link to organized crime lurks in Trump’s past Atlantic City dealings. He had a close association with Kenny Shapiro, an investment banker for Scarfo. According to secret recordings of then Scarfo attorney Robert F. Simone, Shapiro was intimately involved with bribing Atlantic City Mayor Michael J. Matthews, whose term would end in 1984 with a conviction on extortion charges. On the tapes, in 1983, Simone, talking about Leonetti, states: “He’s a nice-looking boy…Nicky’s nephew, he can sit with the…mayor. Ah, and Kenny’s (Shapiro) got the mayor through this kid Phillip.”

The Connections Don’t End in Atlantic City

Trump’s association and business dealings with known mafia figures was not limited to his Atlantic City projects. In New York City, several of his buildings were built by S&A Concrete Co., a concern partly owned by Anthony “Fat Tony” Salerno, the boss of the Genovese crime family. In addition to this business relationship, Trump and Salerno were both represented by high-power attorney Roy Cohn. In his book, Barrett cites an anonymous source who confirms that on at least one occasion Trump and Salerno had a sit-down in Cohn’s apartment. Trump has denied this claim in the past.

How can the candidate who promises to secure the border and bring good jobs back to America explain having farmed out good-paying jobs to a bunch of illegal immigrants?

Is it reasonable to assume that Trump had no idea that S&A was run by Salerno’s Genovese borgata when Trump’s own attorney was so closely linked to that organization? After all, if Trump (who likes to point out that he has “one of the highest IQs”) is as smart as he would have everyone believe, how could he have been so naive?

Another issue that needs to be addressed in Trump’s New York operations is the use of undocumented Polish workers to demolish the Bonwit Teller building, which made way for the Trump Tower. Only a handful of union workers from Housewreckers Local 95 were employed on the site, the vast majority were illegal Polish alien workers, toiling under inhumane conditions, and wildly underpaid. Trump and his associates were found guilty in 1991 of conspiring to avoid paying pension and welfare fund contributions.

Two questions arise from this. First, how did Trump get away with using such obvious scab labor without raising the ire of local 95? More importantly, how can the candidate who promises to secure the border and bring good jobs back to America explain having farmed out good-paying jobs, legally entitled to American workers, instead to a bunch of illegal immigrants? When the rubber hit the road Donald Trump didn’t walk the walk, he lined his pockets and sold out American workers.

Is it possible that Trump was simply involved in an industry which in the early 1980s was so infiltrated by the mafia that he couldn’t help but have tangential ties? Could this myriad of associations, points of contact, and shared affiliations with known mobsters just be the price of doing business in that business at that time? Sure. And if Trump were just a private citizen, businessman, and reality TV star, he would be under no obligation to explain any of this. But he isn’t. He is the frontrunner for the Republican nomination for president of the United States.

Donald Trump Has Explaining to Do

As one of a handful of people within reach of the most powerful office in the world Donald Trump must explain why so much of his early career is peppered with appearances by powerful underworld figures. Had Marco Rubio, Rand Paul, or Scott Walker bought so much as a used car from a known mafioso, it would be front-page news. Trump bought a piece of land for $1 million from the son of Philadelphia’s former mafia Don, and used it to launch a gambling empire.

The major investigative news outlets in this country with the resources and wherewithal to seriously scrutinize Trump’s ties to the mob need to start doing so.

It isn’t only Trump who has a responsibility here. The news media, which is enjoying his playful romp through electoral politics, needs to wake up on this story. Trump isn’t just fooling around this time. He wants to play in the big leagues, and in the big leagues they play hardball. The major investigative news outlets in this country with the resources and wherewithal to seriously scrutinize Trump’s ties to the mob need to start doing so, sooner rather than later.

Former mafia members need to be interviewed. Transcripts of wiretaps and interviews with the major players in Atlantic City and New York crime syndicates need to be reviewed. The work of Barrett and Johnson, among others over the past decades that show Trump’s underworld connections, need to be re-examined. Gary Hart and John Edwards learned that a serious run for president exposes all the dirty laundry, Trump needs to know that truth applies to him, too.

It’s time to stop treating Trump as a sideshow. He is being treated with kid gloves because nobody thinks he can win. Everybody is simply waiting for him to implode under the pressure of his own enormous ego and unfiltered motor mouth. But rather than plunging his run into chaos, his racist ramblings about immigrants and undignified digs at John McCain’s military service have excited some supporters. They think he speaks truth to power. They think he is the only honest man in politics. And no degree of exasperation from level headed news people and party officials seems to tamp his populist surge.

Being a loudmouth bigot, the Archie Bunker of 2016 who says what people are too afraid to say, is working well for Donald Trump. But it’s time to hold his feet to the fire. This is a man who did a significant amount of business with mass murderers whose plunder of public and private funds added up to billions. What did he know about them? Maybe more importantly, what do they know about him?

We need to welcome Donald Trump to his new place in serious national politics with a cold, hard look at the crooks, conspirators, and criminals who peopled his early career. Either the Donald will attempt to weather such scrutiny, or he will disappear from the race under it. Either way, that scrutiny needs to start now.