Armed with 8-inch scissors, the group would arrive at the homes of Amish families in rural Ohio after dark and attack the men inside, holding them down as they sheared their beards and left them emasculated and humiliated.
The Amish, whose beards carry religious significance, told federal authorities it was an assault worse than being beaten.
The attackers told their victims it was religious punishment.
On Wednesday, the U.S. Attorney's office labeled the attacks hate crimes and announced it would federally prosecute Sam Mullet, a former member of the mainstream Amish who formed a breakaway sect, and six others from his group.
If convicted of the crimes, the men face up to 10 years in prison. But if prosecutors can successfully argue that kidnapping was an element of the crimes, they could face up to life in prison, said Michael Tobin, spokesman for the U.S. Attorney's office in Cleveland.
"When people commit crimes ... based on somebody's religion, the community that's victimized is far broader than the victim of the attack," said U.S. Attorney Steven M. Dettelbach. "A message goes out to all people that they should be fearful of their exercise of belief."
The FBI and sheriff's deputies from Jefferson County, Ohio, raided Mr. Mullet's compound in Bergholz before dawn and arrested the seven without incident.
In addition to Mr. Mullet, agents arrested three of his sons: Johnny, Lester and Daniel, along with a nephew, Eli Miller, and a minister, Levi Miller, who is unrelated to the Mullet clan.
Also arrested was Sam Mullet's son-in-law, Emanuel Shrock, who was implicated in the most recent beard-cutting attack against his own father in Jefferson County.
The charges are the culmination of an investigation that required extraordinary efforts on the part of local law enforcement -- one detective was raised Amish -- who convinced the victims to report the attacks and provide information to authorities, said Steven Knowling, prosecuting attorney in Holmes County.
Mr. Knowling said that certain crimes often don't get reported because the Amish prefer to resolve matters internally.
"Our sheriff was able to gain their trust. That's how we were able to identify who they were," he said.
Mr. Knowling arrested and charged five of the men last month, but agreed to drop his state case in favor of federal prosecution.
According to an FBI affidavit, Mr. Mullet and other Amish leaders have been feuding for years because of accusations that Mr. Mullet, the bishop in Bergholz, runs his community like a dictator, doling out discipline for disobedience that includes beatings and forcing men to sleep in a chicken coop for days at a time.
Sam Mullet also has taken women into his home to "cleanse them of the devil with acts of sexual intimacy," the affidavit said.
That accusation echoes long-standing claims of sexual misconduct raised during a protracted federal civil suit that Mr. Mullet filed against Jefferson County Sheriff Fred Abdalla over a 2007 incident in which the sheriff removed Mr. Mullet's daughter's children from the Bergholz compound to enforce a custody order.
As part of that case, lawyers explored the nature of Mr. Mullet's conduct in Bergholz.
In a deposition from September 2009, Mr. Mullet admitted that he asked wives about their sexual practices, especially oral sex. He said he did so because the wives had confessed to him that they were engaging in sex acts that they thought were wrong.
But Sheriff Abdalla said he has long been told Mr. Mullet sleeps with the wives of men at Bergholz and locks up the husbands in a chicken coop if they complain.
Mr. Mullet has not been charged with any sex crimes.
The FBI affidavit provides a timeline for events leading up to the beard-cuttings, beginning from the time in 2003 when Sam Mullet became the bishop in Bergholz.
In 2005, eight families moved away from Bergholz because they didn't like how Mr. Mullet was running the church and the community. As a result, Mr. Mullet ex-communicated those families, the FBI said. Other Amish bishops then questioned whether that action was consistent with Amish customs and scripture.
In 2005 or 2006, the affidavit said, 300 church leaders met in Ulysses, Pa., to discuss Sam Mullet and his clan. Seven bishops selected to examine his practices determined that the ex-communication would not be recognized because they said Mr. Mullet had acted out of revenge to punish the families for leaving his fold.
The families were allowed to relocate to other Ohio counties, including Trumbull and Carroll counties.
The beard-cuttings, according to the FBI, were in retaliation for the actions of the bishops in effectively overturning Mr. Mullet's decision to ex-communicate the eight families.
One of the bishops who was among the seven involved in the decision had his beard cut on Oct. 4, according to the affidavit, when Mr. Mullet's sons and followers attacked the man at his house in Holmes County.
During that attack, the bishop pleaded with the Mullet clan not to cut his beard. One attacker told the bishop that since he was a Christian, he should not resist. When the bishop replied that the attackers were also Christians, one of the men said, "We're not Christians," according to the FBI. The men then sliced off his beard and cut his head, leaving him bleeding.
A few hours later, according to the affidavit, the men attacked another bishop in Carroll County. In each attack, the FBI said, one member of the Mullet clan used a camera to record images of the shorn bishops.
The FBI also said Johnny Mullet, Lester Mullet, Daniel Mullet and Eli Miller all confessed to beard-cutting crimes in interviews with sheriff's deputies in October.
In addition, Johnny Mullet said he discussed the attacks with his father, although he said Sam Mullet did not send him to carry them out. Johnny Mullet said the beard-cuttings were committed out of "anger and revenge," according to the FBI.
Sheriff Abdalla, who has battled Sam Mullet for years in court, has long described him as a dangerous cult leader, but had been unable to gather enough evidence to charge him with a crime.
Last month, however, the sheriff and his counterpart in Holmes County, Tim Zimmerly, asked the FBI in Cleveland for help. Sheriff Abdalla said agents from the FBI office in Canton, Ohio, quickly pieced together a historical case against the Mullets.
The seven are charged with hate crimes, conspiracy to commit hate crimes and aiding and abetting. They faced an initial appearance Wednesday before Federal Magistrate Judge George J. Limbert, who held them without bond at the request of the federal prosecutor.
They will be held at a federal detention facility in Youngstown at least until next week, when they go back before a federal judge for preliminary examination and detention hearings.