The U.S. House Ethics Committee will investigate Democratic Representative Shelley Berkley, further complicating her bid to win a hotly contested and closely watched Senate race.
The 10-member panel said in a statement on Monday that it had voted unanimously to probe allegations Berkley may have improperly involved herself in an effort to help save a hospital program connected with her husband's business.
Berkley's husband, Larry Lehrner, is a kidney specialist and had a contract with the transplant unit at University Medical Center in Las Vegas when it was threatened with closure.
The issue, which surfaced last year, has already overshadowed Berkley's effort to unseat Republican Dean Heller in November's election.
The tight race is among a handful considered crucial to Democratic efforts to keep control of the Senate led by Harry Reid, also of Nevada. Democrats hold a six-seat majority.
The decision to investigate means that Berkley's campaign may be dogged by the matter for the rest of the Senate race.
Jennifer Duffy, who tracks Senate races for the nonpartisan Cook Political Report, called the ethics panel's decision to investigate "a setback because Berkley seemed pretty convinced that she would be cleared," and no such probe would be ordered.
"It's not fatal, but it's a problem," Duffy said.
Nevada Republicans asserted in their initial complaint to Congress that Berkley would have directly benefited financially from her involvement in the 2008 case due to her husband's links to the hospital's kidney center.
Berkley has said her effort to help keep the center open when it was facing federal action that could have resulted in its closure was not motivated by a potential financial interest. She said she did nothing wrong.
Her campaign manager said on Monday evening that the lawmaker welcomed the investigation.
"We are confident that ultimately it will be clear that Congresswoman Berkley's one and only concern was for the health and well being of Nevada's patients," Jessica Mackler said.
"With more than 200 Nevada patients desperately waiting for a lifesaving kidney transplant, it would have been irresponsible of her not to work with the state's entire congressional delegation to protect the program," Mackler said.
As a member of the House at the time, Heller also joined in the Nevada delegation's efforts to keep the government from closing the kidney unit.
The Ethics Committee conducted a preliminary review before deciding it should create a team to look at whether Berkley's actions - in view of her husband's financial interest - amounted to a conflict of interest and a violation of House rules.
The Ethics Committee includes five Democrats and five Republicans.
"The committee notes that the mere fact of establishing an investigative subcommittee does not itself indicate that any violation has occurred," it said its statement.