Lyle Jeffs, the leader of a polygamous breakaway sect of the Mormon Church, has been arrested nearly a year after he slipped out of home confinement in Salt Lake City where he is facing fraud and money laundering charges, the authorities said on Thursday.

The Federal Bureau of Investigation said in a statement on Twitter that Mr. Jeffs, the de facto leader of the Fundamentalist Church of Jesus Christ of Latter-day Saints, was arrested in South Dakota on Wednesday night and was in custody. Officials said that the authorities, acting on a tip, had found Mr. Jeffs living out of a Ford pickup truck in Yankton, a city of about 14,000 people on the Missouri River.

“We knew that this was just a matter of time,” said Eric Barnhart, the special agent in charge of the Salt Lake City Division of the F.B.I. “He spent that whole time, I am sure, looking over his shoulder,” he told a televised news conference.

Mr. Barnhart said the department would not identify the tipster unless given permission by that person, but he said it was a “good story.” He said the person matched the man in the truck to Mr. Jeffs’s description, took down the vehicle information, and then alerted the authorities.