Reward posters for the “Jeff Davis 8.” (Tyler Bridges/For The Washington Post)

For a state accustomed to explosive sex scandals, the one dominating a U.S. Senate race here simmered for a long time before boiling over into public view last week.

In a new book, “Murder in the Bayou,” author Ethan Brown cites multiple anonymous sources who claim that Rep. Charles W. Boustany Jr., a top Republican candidate for the Senate race, had been the client of three prostitutes who were later murdered. Those women were part of an infamous string of unsolved cases, the “Jeff Davis 8,” that happened here in Jefferson Davis Parish from 2005 to 2009.

The book also reports that a Boustany field staffer, Martin Guillory, operated the Boudreaux Inn, a cheap motel where, Brown writes, all eight women hosted their clients.

Boustany has denied the allegations. He told Brown last spring, as the book was being prepared, that he had never hired prostitutes and said he did not know of Guillory’s connection to the motel.

And without any evidence — Brown will not identify his sources, he says, to protect their safety — most media outlets treated the allegations with caution.

But then suddenly last week, after the book was published, Bridget Boustany defended her husband in an email to supporters, blasting the “media rumor mill and lies” about her husband that she called “false attacks aimed at bringing down a candidate who threatens to take the lead and win the race for U.S. Senate,” she wrote.

That opened a door for his opponents to address the issue — and they burst through it.

Louisiana State Treasurer John N. Kennedy (R), considered the front-runner, issued a statement that began: “I want to be very clear that my campaign played absolutely no role in creating this story alleging Congressman Boustany’s sexual relationships with prostitutes that were later murdered, his staff’s alleged ­­­in­volvement in running the bar and hotel where this illicit behavior took place, or publishing the book.”

The Boudreaux Inn, closed since 2008. (Tyler Bridges/For The Washington Post)

Another Republican candidate, Rep. John Fleming, wrote, “We pray Charles can address these scandalous allegations so we can return the campaign to a discussion of national policy issues rather than instances of alleged personal misconduct.”

Kennedy’s statement was picked up widely, making the allegations the top political story in the state. It also drew critics.

“Kennedy’s people saw that as an opportunity to amplify and make sure that the denial was the story,” said Robert Mann, a historian and communications professor at Louisiana State University who worked in communications for Democratic campaigns during six statewide races. “They’re denying what they’re doing while they’re doing it. It’s pretty breathtaking in its audacity.”

In the aftermath, Boustany fired Guillory. And he dismissed the book’s allegations and ­accused Kennedy of fanning the story when he finally addressed the charges during a short ­telephone news conference last week from Washington with ­Louisiana reporters.

“It is all total lies — and everyone, even John Kennedy, knows it,” Boustany said.

The conference call was unavoidable, Mann said. “You discuss that stuff in public only if you have no choice whatsoever,” Mann said. “Get it over with now, take your lumps and move on.”

Boustany’s campaign press secretary later canceled an interview with the candidate for this story, instead directing a reporter to Boustany’s written denials on the subject.

Before now, the Senate race had been better known for its retiring incumbent, Sen. David Vitter (R), whose own career was mired in a prostitution scandal, and David Duke, the white ­supremacist and former Ku Klux Klan grand wizard who joined the race.

Rep. Charles W. Boustany Jr. (R-La.) speaks on Capitol Hill in Washington in 2011. (J. Scott Applewhite/AP)

Up until now, Boustany, a heart surgeon from Lafayette elected to Congress in 2004, has been ­uncontroversial.

“His reputation is as a very serious kind of representative who studies the issues and is known as a policy wonk,” said Pearson Cross, a political science professor at the University of Louisiana at Lafayette. “He has, as far as I know, not had any taint of corruption, venality or sexual innuendo.”

In the 24-candidate field, the top two finishers in the Nov. 8 primary, regardless of party, will advance to the Dec. 10 runoff election. Kennedy leads in most polls with about 20 percent, with Boustany not far behind. Both are thought to be fighting for the same moderate, conservative ­voters.

A new sex scandal in Louisiana, of course, isn’t exactly a shock. In the late 1950s, Gov. Earl Long openly consorted with a stripper, and Edwin Edwards cracked jokes about his affairs during his four terms as governor. More recently, in 2014, the married Rep. Vance McAllister (R) was caught on leaked surveillance video kissing a married female aide, and he promptly lost his reelection.

Vitter had seemed to successfully dodge the 2007 controversy, when phone records showed calls from Vitter to Deborah Jeane Palfrey, known as the “D.C. Madam.” Vitter held a news conference and confessed to a “very serious sin” — but he left without answering questions. In 2010, he won reelection.

But he lost the 2015 race for governor to a little-known ­Democrat, John Bel Edwards, ­after Edwards and others ­repeatedly raised his character as an issue. Immediately afterward, Vitter announced he would not seek reelection.

The book is resurrecting a painful subject for Jennings, a town of 10,0000 in the middle of Louisiana’s fun-loving, rice and crawfish farming region, known as Acadiana.

Local officials, such as Sheriff Ivy Woods, are unhappy with Brown’s book and the publicity it will bring to the unsolved “Jeff Davis 8” cases.

“I think he just wrote the book to make money and embarrass the people of Southwest ­Louisiana,” said Woods, who added that he had never heard of Boustany having any involvement with the prostitutes.

For his book, the New Orleans-based Brown, who is also a licensed private investigator, said he made repeated trips to Jennings beginning in 2011 to find out what happened to the women. He writes that local law enforcement officials failed to secure crime scenes and moved slowly because the women were poor drug addicts.

In an interview, Brown said he believes the murders were committed by more than one person.

The Jeff Davis 8 all knew one another. All were from Jennings’s south side and became trapped in a life of abusive men, drug addiction and prostitution to pay for the drugs. Their deaths became notorious because law enforcement officials, despite forming a state and federal task force, ­haven’t solved any of the cases.

“If you don’t get involved in illegal narcotics, Jennings is a wonderful place to raise a family,” said District Attorney Michael Cassidy, as he dug into a lunch of fried catfish and boudin, a local sausage served in a natural ­casing. “The ones living that ­high-risk lifestyle, their friends and family did not realize they were in danger.”

Cassidy also said he believes that more than one person committed the murders.

Andrew Newman, 55, the father of one of the victims, Kristen Lopez, remembered her “as a slow learner who was just getting out there in life.”

Lopez was 21 in 2007, when her body was found in a drainage canal outside of town on Highway 99. Newman was in prison at the time, he said, for smoking crack. He also admits that he smoked crack with his daughter.

Andrew Newman by the cross where the body of Kristen Lopez, his daughter, was found. (Tyler Bridges/For The Washington Post)

On Saturday, Newman spent several minutes rooting through tall reeds before finding the chest-high wooden cross that marks the spot where her body was found.

“Whoever did it will one day die,” he said while leaning on the cross. “They got to answer to the Lord. God provides the last ­judgment.”