In the weeks since Donald Trump ignited a firestorm by claiming "thousands and thousands" of Muslims in Jersey City cheered the fall of the twin towers on 9/11, elected officials, religious leaders and a former state attorney general denied the existence of celebrations in the city that day.

Media outlets, after scouring archived news stories and video footage, could not find verified accounts of Jersey City Muslims rejoicing.

But in a new examination by NJ Advance Media, a police officer who worked on 9/11 and residents on the outskirts of Journal Square say they witnessed small pockets of people celebrating before the groups dispersed or were broken up by authorities.

The NJ Advance Media inquiry, encompassing more than two dozen interviews conducted since Nov. 25, found Trump's broad assertion that thousands of people cheered to be baseless. At the same time, the inquiry provides the first credible indication of at least two modest celebrations, as described by on-the-record sources who say they witnessed the behavior.

"When I saw they were happy, I was pissed," said Ron Knight, 56, a Tonnele Avenue resident who said he heard cries of "Allahu Akbar" as he shouldered his way through a crowd of 15 to 20 people on John F. Kennedy Boulevard that morning.

Collectively, the gatherings amounted to dozens of people at the two locations, the witnesses said. Callers also flooded the 911 system with accounts of jubilant Muslims on a rooftop at a third location, three police officers said, but a reporter was unable to find witnesses there 14 years later.

Among the news organization's findings:

* A retired police captain, Peter Gallagher, said he cleared a rooftop celebration of 20 to 30 people at 6 Tonnele Ave., a four-story apartment building with an unobstructed view of Lower Manhattan, in the hours after the second tower fell.

A Google Earth view of 6 Tonnele Ave., the triangular building at center. Jersey City police cleared a group of celebrating Muslims from the roof on 9/11, a retired captain says.

"Some men were dancing, some held kids on their shoulders," said Gallagher, then a sergeant. "The women were shouting in Arabic and keening in the high-pitched wail of Arabic fashion. They were told to go back to their apartments since a crowd of non-Muslims was gathering on the sidewalk below and we feared for their safety."

FBI agents took several residents of the building into custody days later, according to neighbors and an account in The Star-Ledger. It is unclear why they were detained.

* Knight was one of two Tonnele Avenue residents who said they witnessed a crowd celebrating on John F. Kennedy Boulevard not far from Masjid Al-Salam, the mosque where Omar Abdel-Rahman, known as the "blind sheikh," preached before the 1993 World Trade Center bombing.

Carlos Ferran, 60, who lives in the same building as Knight, said he was on his way to a liquor store to buy beer when he came across the gathering on the sidewalk.

"Some of them had their hands in the air," Ferran said. "They were happy."

* Numerous people called police to report an exultant crowd on the roof of 2801 John F. Kennedy Blvd., a distinctive, five-story apartment building at the intersection of Sip Avenue, said retired officer Arthur Teeter, who worked in the radio room at police headquarters on Sept. 11.

Officers were dispatched to the address at least twice but were delayed getting inside because the front door was locked, said another retired officer, Bruce Dzamba.

"By the time I got to the roof, no one was there," Dzamba said.

The building was cited in a Sept. 16, 2001, WCBS television news clip in which reporter Pablo Guzman, citing unnamed sources, said federal officials had detained eight men seen cheering on the roof. That account could not be independently verified.

Teeter, the officer who worked in the radio room, said the address was one of several where 911 callers cited rooftop celebrations.

"There were enough calls that it was disturbing," he said. "That's the only word I can use."

* Three additional officers who remain on the Jersey City force said they witnessed small groups of Muslim celebrants on Sept. 11, but they would not speak for attribution, citing a department policy that prohibits media interviews.

The officers, including a high-ranking official, said their reluctance to speak publicly also stemmed from concern they would run afoul of Jersey City Mayor Steven Fulop, who has repeatedly said celebrations did not take place.

"I saw it with my own eyes," the ranking officer said. "In the end, police officers are professionals, so we just observed that stuff and sucked it up."

Eleven other officers claimed to have been witnesses to celebrations in postings on Facebook after Trump resurrected the issue, but they either declined to speak for attribution or did not return calls seeking comment.

A SEARCH FOR THE TRUTH

NJ Advance Media launched its inquiry to determine the truth about an issue that proved deeply disturbing to Americans in the immediate aftermath of the attacks and that has flared anew with the declaration by Trump, the leading candidate for the Republican nomination for president.

Told of the findings, Fulop remained skeptical, saying in an interview that staff from the police department and the city clerk's office have found no documentary evidence to support the claims.

Jersey City Mayor Steven Fulop, seen here at a Dec. 3 press conference in which religious and political leaders denounced Donald Trump, says there is no record of Muslim celebrations in Jersey City on 9/11. (Reena Rose Sibayan | The Jersey Journa)l

"There are no records of this, and over time, what has happened is that it has become urban legend in many cities where people say they heard or saw something," Fulop said, adding that it is harmful to Jersey City and the Muslim community to perpetuate the stories. "At the end of the day, the only thing we can go on are facts. There is no media record. There is no police record. There is nothing."

The mayor questioned why Gallagher, the retired captain, did not file a report.

"In the days after 9/11, with heightened awareness and heightened scrutiny, the fact that he didn't document it leads to one of two conclusions: Either he wasn't doing his job, or it never happened," Fulop said.

Gallagher, 67, said the task was one of many he completed on what was almost certainly the busiest day in the history of the Jersey City Police Department and that the celebration did not amount to a crime.

"At the time, the assignment to clear the sidewalk and roof was what the JCPD calls a DG (disorderly group) call," he said. "If no violence is involved it is, and was, a minor assignment. The people on the roof were cooperative as were the people on the sidewalk. No report was necessary."

Two former Jersey City police chiefs, Tom Comey and Robert Cowan, said they were not in the Journal Square area on 9/11 and did not witness anyone cheering. Both, however, spoke highly of Gallagher.

"I would have no reason to doubt Pete," Comey said. "He's a man of high integrity."

Cowan said he worked with Gallagher for many years, calling him a "good cop." The former chief also defended Gallagher's reasoning in not filing a report, saying it was "pandemonium" in Jersey City that day and that reports typically are not filed unless a crime is committed.

"If you took a report for everything that went on that day, you would have had all the cops off the street," he said.

The current police chief, Philip Zacche, responded to a request for an interview with a one-line emailed response: "Didn't see any celebrating."

Peter Behrens, who served as chief on Sept. 11 and who has since retired, could not be reached for comment.

NJ Advance Media filed a request for public records from the police department's computer-aided dispatch system, which tracks 911 calls and provides a synopsis entered by dispatchers at the time of a call.

On Dec. 11, Jersey City requested a two-week extension to fulfill the request, initially submitted Dec. 2.

Officers said the police department forwarded reports of all manner, including those describing suspicious activity, to the FBI in the wake of the attacks. Special Agent Celeste Danzi, a spokeswoman for the agency's Newark division, declined to comment on reports of celebrations. A request for comment from FBI headquarters was referred back to Newark.

6 TONNELE AVE.

Gallagher, who retired in 2010, said he is speaking out solely to set the record straight and not for any political purpose.

Though scheduled to be off on Sept. 11, Gallagher said, he went to work, as most Jersey City officers did, after learning planes had struck both towers.

Gallagher, who then headed up the warrant squad, said he was assigned four officers he didn't know and sent to the Journal Square area.

A view of 6 Tonnele Ave. in Jersey City. A retired police captain says a group of 20 to 30 Muslims celebrated on the roof after the twin towers fell on 9/11. (Mark Mueller | NJ Advance Media)

Once there, he said, he was directed by a superior officer to clear a roof at Academy and Van Reypen streets between 11:30 a.m. and 12:30 p.m. Gallagher identified the address as 6 Tonnele, which sits at the intersection of Tonnele Avenue and Van Reypen Street, some 50 feet from Academy Street.

The priority, he said, was to head off a confrontation between the growing number of non-Muslims watching from the street and those on the roof. Within minutes, he said, it was over.

The residents -- six to 10 men, a larger number of women and a handful of children -- went back to their apartments without protest, he said, and he and the other officers cleared those on the street.

Gallagher said he does not recall the names of the other officers because he was not familiar with them. He said he believes accounts from other officers he's spoken to that describe similar small celebrations.

"The celebrations happened," he said. "All or most on rooftops. The JCPD leadership put out an order to seek the cooperation of the Muslim celebrants for their own safety. By 2 p.m., there were no more celebrations and my squad was designated a roving patrol to guard about six mosques."

A reporter was unable to access the Tonnele Avenue roof, and a half-dozen residents who were interviewed said they did not live there on 9/11.

David O'Neill, the superintendent of a nearby building, 20-22 Tonnele Ave., said he was on his building's roof most of the day, watching the smoke-shrouded Lower Manhattan skyline to the east.

He said he did not see a crowd on the roof of 6 Tonnele, some 100 feet to the south, though he did recall police blocking off the street at one point.

At center, the roof of 6 Tonnele Ave. in Jersey City, as seen from the roof of 20-22 Tonnele Ave., about 100 feet to the north. (Mark Mueller | NJ Advance Media)

Knight, who said he saw the group on John F. Kennedy Boulevard and who lives at 20-22 Tonnele, said he was with O'Neill on the roof from about 11 a.m. to 3 p.m. off and on. The two grow vegetables there in the summer and have a few beers and enjoy the view on other occasions. Knight said he, too, did not see a crowd on the roof of 6 Tonnele.

Just over half of the roof is clearly visible from 20-22 Tonnele. The far side -- adjacent to Van Reypen Street -- is obscured by structures on the roof of 6 Tonnele.

On the morning of Sept. 11, Knight said, he had been working at a printing company in Lower Manhattan when the first plane struck. The second plane hit as he raced to the Christopher Street PATH station, he said, adding that he believes he caught the last train out before service was suspended.

He said he remembers the celebratory gathering on John F. Kennedy Boulevard vividly because the group's delight was so jarringly out of context with the grim expressions worn by everyone else, including other Muslims, he saw that day.

"I think about that day all the time," Knight said. "It stays with you."

REVIVING A CONTROVERSY

Accounts of celebrations in Jersey City and Paterson, both of which have large Arab-American and Muslim populations, spread quickly in the days after the attacks. Most accounts have been debunked.

As years passed, the claims fell into dormancy.

Trump revived them during a Nov. 21 campaign stop in Alabama, making national headlines.

"Hey, I watched when the World Trade Center came tumbling down. And I watched in Jersey City, New Jersey, where thousands and thousands of people were cheering as that building was coming down," he said. "Thousands of people were cheering. So something's going on. We've got to find out what it is."

Donald Trump, seen here at a campaign rally in Myrtle Beach, S.C., claimed on Nov. 21 that "thousands and thousands" of Muslims celebrated in Jersey City on 9/11. Witnesses have told NJ Advance Media they saw small pockets of celebration, but Trump's broad claim is baseless. (AP Photo/Willis Glassgow)

Trump doubled down in an interview a day later, insisting he saw cheering people in New Jersey on television, though no such footage has been discovered.

Jersey City officials quickly issued statements denying Trump's claim. Fulop later joined with community leaders, imams and clergy members of other faiths at a Dec. 3 press conference to condemn the candidate and his comments.

Separately, former Attorney General John Farmer Jr. wrote in an opinion piece Nov. 24 that as disturbing as the accounts were, no one found evidence to support them.

"We followed up on that report instantly because of its implications if true," Farmer wrote. "The word came back quickly from Jersey City, later from Paterson. False report. Never happened."

In an interview with NJ Advance Media Saturday, Farmer called Sept. 11 "total chaos," with "a zillion reports we had to chase down, 99.9 percent of which were baseless."

The reports of celebrations in the Journal Square area, he said, were especially worrisome given the neighborhood's connection to the 1993 World Trade Center bombing.

"That was a neighborhood known to harbor people who had sympathies," Farmer said.

But when authorities investigated the reports of cheering that day, they found nothing to substantiate the claims, he said. On Sept. 12, 2001, Farmer said, he visited the neighborhood and found a climate not of joy but of fear, with Muslims worried about reprisals.

"Would it surprise me to know there were small groups of people in that neighborhood who might have been happy? No," Farmer said. "But was it on a scale that would have caused us to send in the troops and suppress a riot? No."

The former attorney general cautioned that eyewitness testimony -- absent documentation to back it up -- is notoriously unreliable. And like Fulop, he questioned why Gallagher didn't file a report or alert his superiors.

"The officer chose to treat whatever he saw and did as a non-event, not even worth recording for intelligence purposes," Farmer said. "I have no reason to doubt that something happened, but I think the officer's non-action speaks volumes about the significance of whatever did occur."

THE SEVILLA

Of all the reported celebration sites in Jersey City, the rooftop at 2801 Kennedy Blvd., a building known as the Sevilla, is repeated most frequently, officers say.

"That's always the first building everyone talks about," said Teeter, the retired officer who worked in the radio room.

Asked if some 911 calls that came in that day about the address were second-hand accounts, the product of a proverbial echo chamber on a traumatic day, Teeter said the callers reported seeing people on the roof with their own eyes.

"They said they were witnessing this," he said. "We don't send out cars based on someone saying somebody else saw it."

Retired police Capt. Joe Ascolese, who was working elsewhere in the city, remembers hearing a police radio call about the address. Ascolese was familiar with the building, he said, because he had once searched for a murder suspect on the roof.

After planes struck the twin towers, numerous Jersey City residents called police to report Muslims celebrating on the roof of this building, 2801 John F. Kennedy Blvd., an apartment building known as the Sevilla, retired officers say. (Mark Mueller | NJ Advance Media)

"I don't remember the exact words, but it was to the effect of a large amount of people on the roof, and they were celebrating, and we had to check it out as a hazardous condition given the background of what had just happened," Ascolese said, adding that he did not personally respond.

A longtime resident of the building said that on Sept. 11, three other residents independently told her people were cheering on the roof.

"As a good American, as a good person, it made me angry," said the woman, 88, who insisted on being identified by her formal married name, Mrs. Robert Evans. She was interviewed in the presence of the building's superintendent, Jose Cespedes.

Evans, who has lived in the building for 48 years, said the other residents have since moved. The Sevilla has had a high turnover in recent years, Cespedes said, noting it once had far more Arab-Americans. Cespedes said he was not the super in 2001.

A reporter was recently granted access to the roof, which offers panoramic views of New Jersey and Manhattan. The Capital One bank building in Journal Square blocks the view of the World Trade Center site, but smoke would have been visible.

To local Muslim leaders, the persisting reports of celebrations are deeply frustrating, and they worry about a possible backlash.

"If anyone has a video or a media report showing this, please bring it up, and it will be evidence against those groups, not all Muslims," said Imam Kamal El-Sayegh, the spiritual leader at Masjid Al-Salam. "Our children and grandchildren are here in this country. We don't want to destroy it. We want to keep it safe."

Mark Mueller may be reached at mmueller@njadvancemedia.com. Follow him on Twitter @MarkJMueller. Find NJ.com on Facebook.