A breakaway Amish cult in Ohio headed by leader Samuel Mullet terrorised the local Amish population by forcibly cutting the hair of men and women in night-time raids.
Seven members of his group have been arrested by U.S. authorities for perpetrating physical attacks on other members.
Jefferson Country Sheriff Fred Abdalla said that Amish communities in three states had been traumatised by the attacks.
"You've got Amish all over the state of Ohio and Pennsylvania and Indiana that are concerned. We've received hundreds and hundreds of calls from people living in fear," Mr Abdalla said.
"They are buying Mace, some are sitting with shotguns, getting locks on their doors because of Sam Mullet."
The men have been charged with hate crimes for carrying out "religiously motivated physical assaults" and causing injury by use of a dangerous weapon.
The Amish, a deeply religious group who live by strict adherence to the Bible, believe that cutting the hair on the head and of a man's beard is prohibited by God. One victim of the gang told the FBI he would rather be "beaten black and blue than to suffer the disfigurement and humiliation of having his hair removed," reports the Washington Post.
Mullet ran his breakaway cult from the town of Berdholz, Ohio, and says he did not order the haircutting but didn't stop his sons and other men from carrying it out.
He is also accused of having sexual relations with married Amish women in order to "cleanse" them from the influence of the devil.
Mullet said the goal of the attacks was to send a message to other Amish that they should be ashamed of themselves for the way they marginalised him and his followers.
"They changed the rulings of our church here, and they're trying to force their way down our throat, make us do like they want us to do, and we're not going to do that," he said.
"You have your laws on the road and the town - if somebody doesn't obey them, you punish the people. But I'm not allowed to punish the church people?"
An estimated 61,000 Amish live in Ohio, which has the second largest Amish population in the U.S. after Pennsylvania. Most Amish live in rural communities and shun the use of modern technology. They are not permitted to drive cars or cut their hair, and most travel by horse and cart.