The House Ethics Committee on Thursday voted to start a formal investigation into whether Rep. Laura Richardson (D-Calif.) compelled her Hill staffers to attend campaign events, run personal errands and work on her re-election effort in violation of Congressional ethics rules.

An announcement regarding the details of the investigative subcommittee, whose existence was first reported by the Los Angeles Times late Thursday, is expected sometime today.

Richardson in a statement criticized the investigation — the second in as many years for the California lawmaker — as a discriminatory move made by an Ethics Committee that unfairly targets some Members and ignores the similar actions of others.

“The Committee has chosen to unjustly target its investigations concerning use of official House resources for political purposes on certain members, while overlooking the well-publicized misuse of official House resources for personal purposes by numerous other Members of Congress,” said Richardson, who is African-American. “I also intend to explore the issue of whether the Ethics Committee has engaged in discriminatory conduct in pursuing two investigations against me while simultaneously failing to apply the same standards to or take the same actions against other Members — of whom the overwhelming majority are white males.”

The Ethics Committee last year investigated an unorthodox financial transaction that allowed Richardson to repurchase a home that had fallen into foreclosure and cleared the lawmaker of wrongdoing.

The initial stages of the probe into the improper use of official staff began at least a year ago, when Richardson’s office confirmed that the Ethics Committee had “interviewed staff but has not launched an investigation” into the matter.

The government watchdog group Citizens for Responsibility and Ethics in Washington in June released a cache of emails that showed Richardson staffers were asked to attend fundraising events and wear T-shirts that had the official House of Representatives logo. The emails were exhibits that accompanied a request sent to the FBI that asked for an investigation into the improper use of official government resources for re-election efforts.

Back-to-back ethics investigations have proven costly for Richardson. Her campaign account reported owing $460,011 and had just $116,706 in cash on hand at the end of September, according to its most recent report filed with the Federal Election Commission. More than $125,000 of the debts listed are to law firms.