Outside a nonunion hotel construction site in Midtown Manhattan, a familiar scene unfolded last September: several hundred construction workers gathered to chant pro-union slogans.
To Robert James, an organizer for the laborers union, the rally seemed unremarkable.
That impression changed seven months later, when the Manhattan district attorney’s office notified Mr. James that he had been indicted on charges of coercion, inciting to riot and unlawful assembly. A second organizer was charged with assault, as well as riot and unlawful assembly.
The indictment of the two union organizers is the latest chapter in a six-year battle between the construction unions and a prolific hotel developer and his contractors over substandard wages. It has become a cause célèbre among labor leaders, in part because the presumed victim in the case, Cava Construction, is owned by a reputed member of the Genovese crime family, Carmine Della Cava. Mr. Della Cava, who was the driver for the boss of the Genovese crime organization in the mid-1980s, was convicted of a huge bid-rigging scheme in the 1990s.
“It’s a brave new world when the district attorney’s office sides with a convicted member of organized crime against union workers exercising their First Amendment privilege,” said Mr. James’s lawyer, J. Bruce Maffeo, a former federal prosecutor. “Bob James committed no crime, and this is not a fight from which he or union labor will walk away.”
The three-page indictment of Mr. James and a co-defendant, Dennis Lee, is spare on details of the Sept. 1 rally on 36th Street, near Avenue of the Americas, where Cava is building a 25-story hotel for the developer Sam Chang. The indictment charges that the two organizers made Cava workers fearful of their safety and that of the property if they continued on the job. It says Mr. James urged his fellow union members to run amok and accuses Mr. Lee of shoving a Cava supervisor, John Moore.
“Union rights are fundamental, but so is the right to work,” said Erin M. Duggan, a spokeswoman for the district attorney’s office. “When one interferes with another in a manner that violates our criminal laws, law enforcement should not hesitate to act.”
A surveillance video showed a mostly peaceful, 30-minute rally. At one point, nearly two dozen workers charged through an open gate onto the construction site, where one man hurled a traffic cone and another a pizza box. The men left within 30 seconds.
Mr. James and Mr. Lee have rejected plea deals offered by the district attorney’s office.
Union leaders, who contend that there was no violence at the rally, said their constitutional rights were at stake.
“We have every intention of standing behind our members and will do everything we can to protect our right to peacefully protest nonunion construction,” said Gary La Barbera, president of the Building and Construction Trades Council, an umbrella group for construction unions. “The police were on the scene and no arrests were made. It was their judgment that there was no illegal activity.”
Something did turn up in one of the surveillance materials concerning Mr. James. A man videotaping a second union demonstration on 36th Street was heard telling his colleagues to photograph Mr. James.
“I need a picture of him getting into that car,” the cameraman said. “I got all the plate numbers. I got everything.” His next word was unintelligible, but what followed was clear: an order to hit Mr. James with a “baseball bat when he comes back.”
No one attacked Mr. James, who is 6-foot-5 and 290 pounds.
Mr. Della Cava did not return phone calls and e-mails seeking comment.
In response to questions about Mr. Della Cava’s conviction for bid-rigging, his lawyer, Alfred T. DeMaria, said: “That was 25 years ago. He’s not doing anything wrong now.”
It is unclear whether the district attorney’s office was aware of who owned Cava Construction before the charges were brought.
Mr. Della Cava was named in a 1986 indictment brought by Rudolph W. Giuliani, then the United States attorney in Manhattan, against Anthony Salerno, the boss of the Genovese crime group; Mr. Della Cava; and others, charging them with labor racketeering, construction bid-rigging, extortion, gambling and murder conspiracies.
Vincent Cafaro, a mob turncoat and a cousin of Mr. Della Cava, submitted affidavits identifying him as the Genovese representative to a mob commission that controlled concrete contracts for high-rise construction in Manhattan. An F.B.I. surveillance photograph from that era showed Mr. Della Cava, who had driven Mr. Salerno to a meeting of the mob’s ruling commission, picking up the mob chief after the session.
In a separate case in 1992, a member of a once-powerful West Side gang testified that Mr. Della Cava was a Genovese “bag man” who paid off corrupt members of the carpenters union.
After several years as a fugitive, Mr. Della Cava was captured and convicted of racketeering in the early 1990s and served 28 months of an eight-year sentence in federal prison in Pennsylvania. He formed his nonunion construction firm after leaving prison in 1994, initially building single-family homes in Westchester County.
Cava Construction is currently building three hotels for Mr. Chang, including the nation’s tallest Holiday Inn at 99 Washington Street, in Lower Manhattan.
Mr. Chang, who has built more than three dozen budget hotels, has been at odds with the carpenters union since 2006, when protests at several of his construction sites on the West Side turned into melees.
In 2009, Andrew M. Cuomo, then the state attorney general, filed a lawsuit against EMC Construction, the contractor used by Mr. Chang before Cava Construction, alleging that it routinely shortchanged immigrant workers and had a three-tier wage system in which Irish workers were paid $25 an hour, black workers about $18 an hour and Latino employees $15 an hour.
The attorney general’s office is currently seeking a default judgment against EMC for $1.6 million in wages and penalties.
In the past year, the carpenters union has held a number of protests at the Washington Street site, where Mr. Chang and Cava are building a hotel with nonunion labor, despite Mr. Chang’s having promised in 2007 to use union contractors.
Last month, Community Board 1, which covers Lower Manhattan, passed a resolution critical of Mr. Chang, citing 6 building violations at the site, $1.6 million in fines and at least $180,000 in unpaid property taxes and fines. Mr. Chang’s company promptly paid the city $80,000 and moved to address some of the violations.
Mr. Chang, who said he was semiretired and spent much of his time in Taiwan, referred questions to his lawyer, Patrick Jones. Mr. Jones declined to discuss the hotel project on 36th Street.
William K. Rashbaum contributed reporting.