Dereck Taylor Holt was charged with aggravated assault, ethnic intimidation, burglary and other offenses for the assault in rural central Pennsylvania that sent all three women to the hospital, according to police.
Holt did not know the women, but it appears he targeted them because they were Mennonite, said Northern Lancaster County Regional Police Chief David Steffen.
Holt railed against the religion during the attack, reading various passages from their Bible and then damaging it, police said.
"This is a hate crime," Steffen told the Intelligencer Journal/Lancaster New Era. He added that police will contact the Pennsylvania Human Relations Commission on Monday regarding the assault.
Holt, who has no fixed address, was arrested Saturday under circumstances that have not been disclosed. He was being held on $1 million bail and it was not immediately clear if he had an attorney.
Holt told the women that he is a former Mennonite, police said. The faith shares a common heritage with the Amish, who shun modern life, but Mennonites are generally more assimilated into mainstream culture.
The victims' ordeal began Friday morning when Holt posed as an insurance salesman to gain entrance to their house in Clay Township, police said.
Holt allegedly attacked two of the sisters, then a third who returned home as the assault was in progress. The women, who are between 84 and 90 years old, were punched, shocked and tied up, according to police.
"They suffered multiple electrical shocks, were incapacitated and left," Steffen told the newspaper. "They were unable to move for a long period of time. That could have led to bad things like blood clots and positional asphyxia."
The women were hospitalized and "are doing remarkably well considering their age," Steffen said.
Holt also allegedly ransacked the house and poured household chemicals on floors and furniture. He fled the brick, ranch-style house about three hours after he arrived, police said; the victims were discovered by a relative a few hours after that.
Steffen did not immediately return a request for comment from The Associated Press. A news conference was planned for Monday.