Washington, D.C. ? A House panel is preparing to accuse Rep. Maxine Waters of at least one ethics violation in her efforts to help a bank with ties to her husband, and the longtime California Democrat plans to fight the charges in a House trial, according to a source familiar with the case.

The allegations were presented Friday to Waters, the source said, speaking on the condition of anonymity because the investigation is confidential.

Waters, an outspoken legislator who has held elective office in Sacramento or Washington for more than three decades, could not be reached Friday night.

The findings on the investigation into Waters by the Office of Congressional Ethics are expected to be made public Monday.