The testimony included an elderly woman’s account of her terror as six of her children and their spouses made a surprise late-night visit, with the men holding down her sobbing husband as they hacked off his beard and hair and the women cut her waist-length hair to above the ears as she prayed aloud.

During the testimony, the 16 defendants, in traditional attire, and their lawyers sat around four tables that took up half the courtroom. In the gallery sat dozens of Amish supporters of the victims, including several of Mr. Mullet’s elderly siblings, who shook their heads as witnesses described his unorthodox methods. Also in the gallery was Mr. Mullet’s wife, who sat impassively as a woman who used to live in Bergholz spoke of how Mr. Mullet pressured her to come to his bed.

The stakes for the defendants were raised when federal prosecutors stepped in to charge Mr. Mullet and 15 others, including several of his children and other relatives, with federal conspiracy and hate-crime charges that carry potential sentences of several decades. Judge Dan Aaron Polster scheduled sentencing for Jan. 24.

The defendants did not deny their roles in the attacks, which were carried out with battery-powered clippers, scissors and razor-sharp shears that are designed to trim horse manes. Rather, the case turned on the motives for the attacks and whether it was appropriate to make them into a major federal case under a 2009 hate-crimes law.

To prove the most serious charges, the jurors had to be convinced that the defendants had caused “bodily injury,” which could mean “disfigurement,” and that the attacks were based mainly on religious differences. Lawyers for the defense argued that cutting hair was not disfigurement and that the attacks resulted from family and personal differences, including a bitter custody battle involving a daughter of Mr. Mullet’s, as well as disputes over the “true” Amish way.

During the trial, Edward G. Bryan, Mr. Mullet’s lawyer, said that his client might have known about the attacks but did not order them. According to testimony, Mr. Mullet stayed up late to greet attackers when they returned to the compound after one of the assaults, accepting a bag of shorn hair as well as disposable cameras used to record the victims’ humiliation. The prosecutors argued that his followers would not have acted without Mr. Mullet’s approval, citing what one of his sisters called the zombielike obedience of Bergholz residents.

Mr. Bryan said Thursday that Mr. Mullet planned to appeal, in part on the grounds that the federal law had been misapplied.