Pike County Sheriff Stephen Korte said Tuesday that Mast sexually assaulted four girls in Missouri and one in Wisconsin who ranged in age from 5 to 15 years old. Two of the Missouri girls were Amish and two weren't, and the Wisconsin victim was his cousin, who is Amish, authorities said.
"It is unfortunate that nowhere is society is anybody immune from being a victim," Korte said Tuesday. "No matter where you go there are people who may violate other people's liberties and freedoms and peace of mind."
Korte and Scott Blader, the district attorney for Waushara County, Wis., said they worried that there may be other victims.
"It looks as though there are other matters out there and we're looking at them actively," Blader said.
Mast is charged in Missouri with two counts of statutory rape, two counts of statutory sodomy and one count of sexual misconduct involving a child. Korte said he is not related to any of those girls. Mast has not entered a plea, and was scheduled to appear in court on Wednesday.
In Wisconsin, Mast is charged with sexual assault and incest. Blader said the victim there is Mast's cousin. He declined to give her exact age at the time of the alleged assault, only saying that she was from 13 to 16 years old.
Mast is jailed on $100,000 bond in Pike County, but if he posts bail, he'll be extradited to Wisconsin and held without bond, Blader said.
Mast did not have a listed attorney, but a request was made through jail officials to interview Mast by phone.
Mast has lived most of his life in Missouri but spent some time in Wisconsin, prosecutors said. The alleged assaults in Missouri happened between July 2007 and March 2009, and the Wisconsin assault occurred in 2004, they said.
Both Pike County and Waushara County have large Amish communities. In Pike County, Mast and most of the 60 or so Amish families live near the town of Curryville, about 90 miles northwest of St. Louis.
Korte and Blader said their offices rarely get reports of serious crimes involving the Amish.
"It is rather unusual," Blader said. "This is probably the first one I've seen."
The Pike County Genealogical Society said the community is "Old Order Amish" that uses no electricity, phones or cars. They travel by horse and buggy, use kerosene lamps for light and gasoline-powered machinery.
Mast worked in a sawmill and farmed, Korte said. He had no previous felony record.