Federal prosecutors have completed their investigation into loans made to Kansas Gov. Sam Brownback's re-election campaign by his lieutenant governor and plan to bring no criminal charges, the U.S. attorney's office said Wednesday.

Jim Cross, spokesman for U.S. Attorney Barry Grissom, told The Associated Press that the office had finished its probe into the loans and was not expecting to file federal charges. Minutes earlier, Brownback and Lt. Gov. Jeff Colyer release a joint statement saying they had been informed there would be no charges after the probe "regarding campaign finance matters."

"As we have stated many times, our campaign finances were conducted in full compliance with applicable law and ethics regulations," according to the statement by the Republican running mates. "We will have no further statements regarding this concluded matter."

The AP was first to report about the federal investigation in January, after obtaining through an open records request a copy of a grand jury subpoena sent to the executive director of the Kansas Governmental Ethics Commission. Brownback's office issued a statement at that time saying the investigation "has no merit," and that any loans were completed in compliance with Kansas law and ethics regulations.

The three loans totaling $1.5 million raised eyebrows not only because their size is unusual in Kansas politics, but because the first two were repaid within days. Democrats speculated they might have been timed to inflate campaign finance reports.  They came as the Republican governor in a deeply conservative state faced the real prospect of losing to the well-financed Democratic challenger, Paul Davis.

Kansas Senate Minority Leader Anthony Hensley, a Topeka Democrat, questioned the decision not to issue any indictments.

"Up until now, they were denying that an investigation was even going on," Hensley said of Brownback and Colyer. "They were denying that there was even an investigation, but as to why the U.S. attorney's office chose not to issue any indictments remains to be a mystery."

During the gubernatorial race, Libertarian candidate Keen Umbehr derided the loans as the "Colyer Hokey Pokey." A spokesman for Davis, who narrowly lost the race to Brownback, said before the election that voters "deserve to know where this money came from."

The Republican running mates have repeatedly refused to disclose the source of those funds, and the government's decision not to file federal charges means the public will likely never learn what the grand jury discovered.

Colyer, a reconstructive plastic surgeon, told the AP in August that the first two short-term loans he made to Brownback's re-election campaign are examples of the good stewardship Kansas residents expect from government officials.

"It was just simple cash management," Colyer said at the time. "It's good money management, that's all. That's what you'd expect for me to do with the state's money, too, is to manage it well. We manage our campaign well, that's it."