The Alliance for a Better Minnesota bills itself as a "grassroots lobbying...organizing group that works with progressive organizations." It's also known as a coalition of Democratic-leaning groups.
The alliance says it sent certified letters to the chairwoman and vice chairman of the U.S. Senate Ethics Committee and the Minneapolis FBI, asking them to investigate whether Coleman violated the Senate code of conduct and the law.
The allegations first arose in a Texas lawsuit filed less than a week before the election.
The suit, filed by the former CEO of Texas-based Deep Marine Holdings, claimed that Minnesota businessman Nasser Kazeminy used the company to funnel money to an insurance company that employs Coleman's wife.
A second lawsuit, filed in Delaware by Deep Marine shareholders, makes similar allegations.
"These are very serious allegations with criminal and ethical ramifications," said the alliance's Donald McFarland. "What actually happened, we don't know. That's why we're here. We'd like to know what actually happened."
When asked whether Al Franken was involved in seeking the investigations, McFarland said his organization did talk to the Franken campaign, and asked it if the campaign were going forward with a letter requesting an investigation. The answer, McFarland said, was "no." So the alliance moved forward.
“What actually happened, we don't know. That's why we're here.”Donald McFarland, Alliance for a Better Minnesota
McFarland also denies the action was politically motivated. He says the group waited until after the election to raise the issue.
Coleman is headed toward a recount in the U.S. Senate race where he currently holds a 206-vote lead over Democrat Al Franken.
In a statement from his campaign, Coleman denied the allegations and suggested he's an innocent bystander in the lawsuits.
Coleman said he and his family are "being used as a tool of extortion by private parties," and that "should be of concern to all Minnesotans."
Coleman said he not only welcomes the investigation, but is also eager to have it move forward immediately.
Former Republican U.S. Sen. David Durenberger of Minnesota faced a Senate ethics inquiry of his own nearly 20 years ago. He said in interview prior to the ethics complaint that it's too early for any investigation about Coleman.
Durenberger says there's no question in his mind that the allegations are politically motivated.
"I see all of this as politics, and it upsets me greatly," said Durenberger. "It reminds me of something I went through. In this case, I don't think this is anything more than a political allegation."
The Senate unanimously denounced Durenberger in 1990 for financial improprieties.
On the Coleman allegations, congressional analyst Norm Ornstein says at this point, there's no proof of anything other than a disgruntled former executive for a company filing a lawsuit against somebody who's known to have a very close relationship with Coleman.
Ornstein is a resident scholar at the American Enterprise Institute in Washington. He says he knows Coleman and considers Franken a friend. He says the ethics charge is all speculation at this point.
"If this turns out that this was indeed simply an effort to get money to the Coleman family from a longtime benefactor of theirs -- laundered in a fashion so that nobody would know that the money was coming, and had nothing to do with any work done by Coleman's wife -- then you've got an ethics issue. But in the absence of that, you don't," said Ornstein.
A spokesman for the U.S. Senate Committee on Ethics said there are three phases to the committee's investigation of a complaint. At the first step, the committee makes a decision on whether the complaint is credible on its face. Iif so, then the committee moves on to step 2.
At that point, the committee authorizes a preliminary inquiry to determine whether a violation occurred -- essentially whether it's more likely than not that ethics rules were broken.
At that stage, the committee has subpoena authority to get records, depose witnesses, and can issue a public or private admonition to the senator.
The third step is reserved for the most egregious rule violations and is more like a court review. at this point, the committee would have found serious rule violations, and can consider censuring or even expelling the senator.
(The Associated Press contributed to this report)