WASHINGTON -- Last week, the U.S. Senate voted to ask the Justice Department to look into what happened in 2005 when Alaska's sole congressman earmarked $10 million in unasked-for money to study a highway interchange in southwest Florida.

The 64 to 28 vote was an unprecedented request on the part of the Senate for a federal inquiry into the actions of a member of the House of Representatives.

At the center of it all: Alaska Rep. Don Young, who acknowledged responsibility last week for the 2005 earmark, which shifted $10 million pledged to help widen Interstate 75 to the interchange study. If built, the interchange promised to benefit one of Young's campaign donors, a family friend whose real estate company owned property nearby. The earmark was one of thousands overseen by Young when he was responsible for pushing a multiyear highway spending bill through Congress.

Young has maintained that there was nothing wrong with what he did, and that the earmark was requested by the community.

But Young is already the subject of a federal investigation, and many questions remain about how the earmark showed up in the spending bill -- after the House and Senate had already voted on an alternative proposal.

What follows is an explanation of where the controversy came from, what's known, and what isn't:

Q. How did the Coconut Road earmark come to national attention?

A. The obscure Coconut Road earmark first came to the attention of transportation planners in Lee County, Fla., in 2006, when they tried to figure out why they had received $10 million in federal money for a study of an intersection that wasn't on their list of transportation priorities.

The transportation board thought it was getting a $10 million earmark to go toward widening of Interstate 75. Instead, the money was earmarked to the study of an interchange that improves freeway access to land owned by real estate developer Daniel Aronoff.

The community was divided over the earmark for the Coconut Road interchange. Although it wasn't on the list of priorities, some organizations, such as Florida Gulf Coast University, had been pushing for the interchange.

Local newspapers, including the Naples Daily News, picked up on the controversy, and posed the question to Young, at the time the chairman of the House Transportation and Infrastructure Committee. In 2005, the Alaska Republican oversaw the multiyear transportation bill, a $286.4 billion spending plan for some of the biggest infrastructure projects across the U.S. (The bill also included $452 million for the Gravina Island and Knik Arm spans that came to be known as the bridges-to-nowhere.)

Young refused to address the issue. The story failed to draw national attention until The New York Times wrote about it last spring. The article elaborated on the connections between the developers seeking the earmark and a 2005 campaign fundraiser Young attended in Bonita Springs, Fla., at the invitation of a local congressman, Rep. Connie Mack, R-Fla. (The article also reported that when a Times reporter approached Young to speak to him about it, the congressman "responded with an obscene gesture.")

Those donating money -- about $40,000 total -- to Young included Aronoff, whose family has long been friendly with Young. The earmark for the interchange study showed up not long after the fundraiser.

Q. How was the earmark put in the transportation bill?

A. It wasn't until August 2007 that anyone realized that there may have been an additional impropriety beyond Young's questionable approval of earmarks that benefited his campaign donors.

In Florida, the head of the transportation planning board asked her friend, Darla Letourneau, to research how the county landed the earmark -- and to determine whether there was a way to use the money how they wanted. Both Mack and Young had suggested it might be poor form to turn down the money, and transportation planners wanted to see if there was a way to keep the money but spend it on road widening.

Letourneau, a retired former congressional liaison to the Department of Labor in Washington, found that as the bill was being cleaned up to be sent to the president, the $10 million earmark was given a specific designation for the Coconut Road interchange. Her research showed that the bill was changed after both the House and the Senate voted on it.

The Web site Talking Points Memo took it one step beyond; researchers looked at 6,373 earmarks in the bill and found that the Coconut Road earmark was the only one that underwent any substantive changes.

Q. What was Young's role?

A. Last spring, Young called the matter "a recycled story" and wouldn't answer questions about it. But as ethics watchdogs, journalists and community activists have uncovered more information, his office has been gradually more forthcoming with the sequence of events.

Initially, they would say nothing other than that the community asked for the change in the earmark and that they made it. In December, they told the Daily News that they always intended for the earmark to go to the interchange study. Florida Gulf Coast University asked for it for hurricane evacuation in 2005 when he attended one of their community transportation meetings.

The actual changes to the earmark came during the enrollment process, when transportation committee staffers from both parties (as well as both the House and Senate) sat down with clerks to fix technical problems with the bill. One of Young's aides on the transportation committee made the change at that time.

Last week, Young's spokeswoman Meredith Kenny told the Washington Post that the bill was altered after both the House and Senate voted on it.

"There was an error in the bill and so it was corrected," Kenny told the Post.

But the change was a substantive one that Congress never voted on, and it angered watchdog groups because it was a clear deviation from regular legislative procedure. They have been calling on the House ethics panel to investigate since Letourneau discovered the post-vote change to the earmark.

Their efforts bore fruit last week when Sen. Tom Coburn, R-Okla., a longtime critic of earmarks and wasteful spending, called for an internal investigation by a bipartisan panel of House and Senate members. The panel would help restore integrity to the legislative process by finding out exactly what happened, Coburn said. His proposal failed and the Senate voted on an alternative: a request for the Justice Department to look into criminal activity connected to the earmark change.

Alaska's two senators, Republicans Lisa Murkowski and Ted Stevens, voted for the failed Coburn proposal but not the Justice Department investigation.

Q. What role will the Justice Department have?

A. The Justice Department already has been investigating. A community activist in Florida told the Daily News last year that he had been interviewed by the FBI in 2006. Investigators wanted to know about the political connections of the people who sought the earmark.

Young has been interviewed by the Justice Department and has provided it with documents, his lawyer, John Dowd, told the Daily News. Dowd said he's advised Young not to talk about "matters under investigation." The Justice Department also requested Young not talk about them, Dowd said. The FBI and Justice have several ongoing investigations, including the wide-ranging probe into political corruption in Alaska. They haven't been forthcoming about their ongoing corruption investigations, because of the sensitive nature of investigating political figures.

But Justice also has refused to even address some of the fundamental questions raised by the Senate's call last week for an inquiry into the Coconut Road earmark. It's not clear whether the Justice Department will investigate, or whether it has the authority to look into an internal, procedural matter.

Q. What role did Florida lawmakers play?

A. Young's office has long tried to cast blame on Connie Mack, pointing to a letter he wrote in support of the Coconut Road study. But while Mack was involved in organizing the 2005 fundraiser in Florida, he was a junior congressman on Young's large House committee. Mack didn't have the authority -- or the position -- to actually change the earmark, unlike Young and the staffers he employed on the committee. While he may have asked for the change, ultimately it was Young's staffers who made it. Mack has denied any involvement but also refuses to discuss the matter.

He, as well as other Florida lawmakers (including the ranking Republican on the House Transportation committee, Rep. John Mica) asked for the earmark to go back to its original format: money for the widening of I-75. They were joined in the Senate by both Florida senators, Republican Mel Martinez and Democrat Bill Nelson. Both the senators voted for the Justice Department investigation.

The Senate's request last week for an investigation was actually attached to legislation that does away with the Coconut Road bill and allows Florida transportation planners to use the money as originally intended: for road widening.

Troubles mount for Rep. Don Young

• On Thursday, the U.S. Senate voted 64 to 28 to ask the Justice Department to investigate Young's $10 million Coconut Road earmark.

• Convicted D.C. lobbyist Jack Abramoff's staff had more than 120 contacts with Young's staff over a 25-month period, according to billing records.

• Young refuses to discuss $1.1 million in campaign funds he has spent on legal fees over the past year.