Occupy Wall Street went down last month. Then came Philadelphia and Baltimore. As officials shut down Occupy encampments across the country, protesters streamed into the District, eager to join the movement in the nation’s capital, which has so far enjoyed protection from supportive local and national police.

The protesters who took over two D.C. parks in October have mostly existed peaceably — setting up elaborate kitchen tents, trucking in portable toilets and even getting police escorts for their marches. But the goodwill has begun to evaporate as protests have become more contentious and some local leaders have begun turning on them.

Last week, pressure intensified when a congressional oversight committee launched an investigation into whether the National Park Service was allowing the Occupiers to camp on federal parkland illegally. Counter-protesters emerged, one toting a sign that said “We want R park back.”

Even the city’s mayor, Vincent C. Gray (D) — who was arrested in an unrelated act of civil disobedience in April — cited increasing frustrations in a television interview Thursday, saying he would ask the federal government to reimburse the city for an estimated $1.6 million in maintenance and policing costs.

“It was a novelty initially, then it became a nuisance and now it’s a concern,” said Jim Dinegar, president and chief executive of the Greater Washington Board of Trade, who has accused the Occupiers of turning McPherson Square into a “toxic waste dump.” “We’ve become the Occupy of last resort. We’ve seen it grow until it’s packed to the gills. You couldn’t get another tent in there.”

Now, with the shift in the city’s attitude, winter approaching, the possibility of congressional hearings and out-of-town protesters continuing to arrive, the Occupy D.C. movement is at a crossroads. Spokesmen for both the McPherson Square and Freedom Plaza Occupy camps have vowed to stay on, but there’s a real question of whether the city and federal governments have had enough.

“I do think more and more people recognize this is where money and power come together,” said Kevin Zeese, an organizer of the Freedom Plaza protest. “People will get that more and more, Washington is the center of action.”

But even as his encampment has grown — to the point that Zeese wonders how they are going to feed the approximately 140 people getting meals each day — organizers are debating whether to move part of their group inside for the winter.

And as the protesters try to figure out their next step, government officials and their lawyers are determining how much leeway they have because decades of legal precedent have codified certain freedoms for protesters in the nation’s capital.

Last week, Rep. Darrell Issa (R-Calif.), chairman of the House Committee on Oversight and Government Reform, which oversees the District, launched an investigation into why the Park Service is allowing the Occupiers to stay in McPherson Square, where they have lived without a permit since Oct. 1. Issa said the Occupiers have torn up $400,000 in new sod and other improvements made to the park in 2010 — and paid for with federal stimulus money.

“This situation raises questions about why those decisions were made, who participated in making them, and whether political judgments played a role in not enforcing the law,” Issa wrote in a Dec. 12 letter to Ken Salazar, the secretary of the Interior Department. That agency oversees the Park Service.

Steve Whitesell, regional director for the Park Service’s National Capital Region, said that although camping is prohibited at the two parks, they believe that the protesters’ First Amendment rights allow them to maintain a “24-hour vigil” there. They are concerned that the protesters adhere to public sanitation standards, however.

“At this point, we have no plans to close the camps,” Whitesell said. “We might decide to at any time we deem that they are noncompliant with the rules and regulations in the parks.”

But Gray sent a testy letter to the Park Service on Friday, saying the city had not been consulted in the decision making about the camps and also asking for the federal reimbursement.

“On behalf of the District of Columbia, I am requesting a full and complete reimbursement for all costs,” Gray wrote. “Our citizens cannot be expected to pay for a consequence in which they had no say.”

Meanwhile, business leaders have raised questions about sanitation and safety around the camps. The U.S. Park Police say that in addition to arrests for civil disobedience, they have charged protesters with drug possession, public urination and other offenses.

Police Chief Cathy L. Lanier also said last month that the police department would get tougher and make more arrests if the protesters stepped out of line. She has followed through, arresting more than 60 in the past two weeks.

After more than 30 protesters were arrested trying to erect a wooden structure — the Occubarn — in McPherson Square, one filed court papers to clarify their rights. That resulted in a ruling by a U.S. District Court judge requiring police to give campers 24 hours’ notice if they plan to evict. A hearing on an injunction is set for Jan. 31. (Editor's note: An earlier version of this story incorrectly stated the hearing was for a permanent injunction.)

Mara Verheyden-Hilliard, a lawyer for the nonprofit Partnership for Civil Justice Fund, said that the matter of whether overnight camping on federal parkland is protected speech was litigated in the 1980s, when the legendary anti-poverty activist Mitch Snyder organized a tent city in Lafayette Park called “Reaganville.

The resulting court case, Clark v. Community for Creative Non-Violence, went to the Supreme Court, which ruled in 1984 that the Park Service had the right to limit overnight stays on parkland without infringing on speech.

“Our argument was that putting up a tent in Lafayette Park was protected speech because it spoke to the nature of homeless and poverty and people living on the streets,” said Carol Fennelly, Snyder’s longtime partner. “The courts found that putting up a tent was protected speech, but sleeping in it was not.”

Occupy D.C. protesters in Freedom Plaza are debating whether to move part of their operation indoors for the winter — they don’t yet know where they might relocate — while maintaining a symbolic presence of tents in the plaza. Their National Park Service permit is set to expire Dec. 30.

One recent night on the plaza, two cooks in the kitchen tent prepared bow-tie pasta and ham with sweet-and-sour sauce over industrial-size propane burners. Lights from a donated Christmas tree twinkled. Bundled-up protesters huddled on folding chairs for their nightly meeting and readied for dinner afterward.

Among them was Stephen Dougherty, 53, a nurse’s aide from North Carolina, who decided to join the Occupy movement to air his concerns about a living wage. He first thought he would head to New York City, but after that camp was shuttered last month, he ended up in Washington.

“I was watching encampments closing down across the country. The energy of the movement is focusing on D.C.,” Dougherty said.

He said hoped the group — which decides everything via consensus — will vote to stay on the plaza through the winter. He showed off his tent, which he bought on eBay for $25 before leaving Asheville.

“I think it’s important there’s always somebody occupying somewhere so the ball doesn’t drop,” he said. “Then in spring, we’ll be on fire.”

Staff writer Tim Craig and researcher Magda Jean-Louis contributed to this report.