(CNN) -- The FBI has arrested three East Haven, Connecticut, police patrol officers and one sergeant for their alleged role in the mistreatment of Latinos -- the first arrests to stem from a federal investigation into racial profiling in that town.

The men allegedly threatened and assaulted detainees, made false arrests -- including one against a local clergy member -- and later conspired to cover up evidence of their conduct by falsifying reports and blocking an investigation, prosecutors said Tuesday during a news conference in Bridgeport.

Sgt. John Miller and officers David Cari, Dennis Spaulding and Jason Zullo were arrested early Tuesday for allegedly conspiring to "injure, oppress, threaten, and intimidate various members of the East Haven community," profiling residents during traffic stops, performing illegal searches and harassing Latino business owners and their advocates, according to the indictment.

"They behaved like bullies with badges," said Janice Fedarcyk, assistant FBI director in New York.

On one occasion on January 21, 2009, Spaulding and Zullo allegedly assaulted two individuals they had arrested under false pretenses, slamming their heads against the station's cell block walls, the indictment said.

The indictment cited a similar incident in which Miller allegedly struck a detainee who was handcuffed after being propped up by two other patrol officers.

The men also dismissed a police commission inquiry into their alleged misconduct, it said, calling on the support of local union leaders to block and intimidate municipal investigators.

The defendants could not be immediately reached for comment, and the East Haven Police Department referred press inquiries to the mayor's office.

"It's unfortunate that it had to come to arrests," said Mayor Joseph Maturo Jr., who said his office "stands behind the East Haven Police Department."

"They're innocent until proven guilty," he said.

Maturo, in an interview with CNN affiliate WPIX, indicated that he saw no problem with not having any Latinos on the East Haven police force. When asked what he would do for the Latino community on Tuesday, Maturo said, "I might have tacos when I go home, I'm not quite sure yet."

The arrests come just weeks after a scathing Department of Justice report, derived from an investigation that began in September 2009, accusing the town's police of engaging in "discriminatory policing against Latinos."

In a letter to Maturo, Assistant U.S. Attorney General Thomas J. Perez said the practice was "deeply rooted in the department's culture," citing statistical analysis that showed Latinos had been "intentionally targeted" for traffic stops.

The letter provided an example of a particular officer's stops, 40.5% of which were of Latino drivers.

Overall, the investigation found that 19.9% of traffic stops made by East Haven police were against Latino drivers, concluding it "shows pervasive discrimination against Latinos on every level of EHPD traffic enforcement activity."

The report also accused some officers of conducting unauthorized immigration investigations.

It mentioned "numerous incident reports" in which officers contacted Immigration and Customs Enforcement to check on the status or seek an immigration detention of a Latino.

Investigators said the tactic was "used to harass and intimidate Latinos rather than pursue legitimate law enforcement objectives."

But Maturo said he doesn't believe allegations of such systemic discrimination in East Haven are accurate.

"We have an open community here," he said.

Maturo elaborated in a news release: "The Town of East Haven is prepared to do all that is necessary to address the consequences of this morning's grand jury indictment. While the Town has several factors to consider, the most important priority is ensuring the continued protection of our Town's residents. To that end, I met with several shifts of officers at our Police Department this morning to ensure that police service to our Town would not be interrupted today and moving forward."

According to 2010 census data, East Haven has a population of some 29,000 people, with about 10.3% identifying as Hispanic or Latino. The vast majority of residents, 88.5%, are white, while close to 3% identify as black or African-American.

Still, Maturo said, there have been changes in the wake of the December report.

An independent commission of community members, external consultants and former law enforcement officials has been formed to head off future allegations by revising police policies.

The mayor cited a series of reforms, including revisions to complaint review policies and training, and pointed to a revised East Haven police handbook, the first update since 1972.

"It was an outdated book," Maturo said.