Police in Bucks County, Pennsylvania, just north of Philadelphia, arrested Lee Kaplan, 51, on Thursday. Police said the girls living with Kaplan at his house ranged in age from 6 months to 18 years.
In a related case, authorities nearly 100 miles away in Lancaster County arrested the parents of the 18-year-old, with police saying the couple had "gifted" their daughter to Kaplan for helping them out of financial difficulties. She was 14 when her first child was conceived, the criminal complaint said.
Kaplan was charged with statutory sexual assault, corruption of minors, aggravated indecent assault, indecent assault and unlawful contact with a minor, according to a police criminal complaint filed in Bucks County.
The 18-year-old's parents, Daniel and Savilla Stoltzfus of Quarryville, are charged with endangering the welfare of children. Daniel Stoltzfus also faces charges of criminal conspiracy and statutory sexual assault, according to a criminal complaint filed by police in Bucks County.
Bucks County District Attorney David Heckler told CNN on Sunday that the Stoltzfuses claimed to be the parents of 10 of the girls, and the grandparents of the remaining two children. The couple are former members of the Amish religion, according to court documents.
Kaplan and Daniel and Savilla Stoltzfus are being held on $1 million bail in the Bucks County Correctional Facility, according to court dockets.
CNN has not been able to reach attorneys for either the Stoltzfuses or Kaplan.
The girls have been kept together in the care of county social services workers, Heckler said.
Neighbor complaint gets police attention
Officers from the Lower Southampton Police Department said they responded to the small white home on Old Street in the Feasterville community on a tip from a neighbor.
Neighbor Jen Betz told CNN she had contacted authorities multiple times about the situation.
"My gut was telling me to confirm what I was thinking. I just knew. There was no reason why this older, significantly older man, any man, regardless of what they look like, would have this amount of children, all in blue dresses, never outside the house regularly, looking so scared," she said. "I knew that something wasn't right."
Kaplan had told neighbors that no children lived with him, according to the complaint.
In his booking photo, Kaplan appears with long gray hair and an unkempt beard. He is the owner of Kaplan Precision Machine Company, according to state corporation filings.
"I really can't believe it, because I really thought it was his own daughter," an unidentified neighbor told CNN affiliate KYW
, referring to the 18-year-old. "It looks like his own daughter to me."
Other neighbors told the affiliate the girls didn't go to school and were rarely let outside.
According to police affidavits, Daniel and Savilla Stoltzfus "came to an agreement" to give Kaplan their daughter after Daniel Stoltzfus "researched the legality of it on the Internet," the affidavit says.
"Stoltzfus stated that his daughter ... was 'gifted' to Lee Kaplan in thanks for helping his family out of financial ruin," the affidavit continues.
Authorities were told by Savilla Stoltzfus that she could produce birth certificates for the 10 older girls, Heckler said. Authorities had not yet obtained birth certificates on Sunday, he said, adding that any such documents and medical tests would determine whether the girls are in fact all the children or grandchildren of the couple.
The district attorney said the investigation is ongoing and, "We don't know what we have."