Former U.S. Attorney for Oregon Amanda Marshall engaged in a yearlong "intimate and personal" relationship with an assistant prosecutor on her staff, violated sexual harassment laws, lied to investigators and tried to block the investigation, an internal inquiry found.

The U.S. Department of Justice's Inspector General announced results of its investigation Tuesday, but didn't name the U.S. Attorney as is common for the agency. Its statement, however, mirrored Marshall's circumstances and she confirmed that the investigation involved her.

She described the relationship as "wrong" and "the biggest mistake of my life." Her lawyer said Marshall initially withheld information to protect her privacy and that of her colleague but later cooperated with investigators.

"By engaging in that affair, I failed the United States Government, my fellow Oregonians, and most of all, my family," Marshall said in a statement. "I am deeply sorry and will spend the rest of my life trying to make amends."

Marshall is now in private practice in McMinnville.

She resigned last year amid allegations that she'd had an inappropriate relationship with a subordinate and later harassed him through emails and texts.

Oregon's current U.S. attorney, Billy Williams, referred all questions regarding the findings to the Justice Department. John Lavinsky, counsel to the Justice Department's inspector general, said he couldn't comment on the investigation.

The inspector general alleged that the unnamed U.S. attorney:

-- Failed to disclose the relationship and continued to participate in work matters involving the subordinate, an assistant U.S. attorney.

-- Sent multiple harassing communications to the subordinate, violating sexual harassment laws and regulations.

-- Lied to Justice Department officials about the relationship when first confronted and ignored the associate deputy attorney general's instructions forbidding contact with the subordinate.

-- Tried to influence the investigation by saying the subordinate was the subject of the investigation and directing the subordinate to get an attorney and not to speak with the inspector general.

Marshall "disagrees with certain of the OIG statements and findings (but) she is gratified that this chapter is closed," her lawyer, Allison Martin Rhodes of the Portland law firm Holland & Knight, said in an email.

Marshall, 47, was nominated by U.S. Sen. Ron Wyden and appointed by President Barack Obama in 2011. Her tenure was marked by the Portland Police Bureau's return to the FBI's Joint Terrorism Task Force, increased prosecutions of child sexual exploitation cases and the conviction of Mohamed Mohamud for trying to bomb the November 2010 holiday-tree lighting ceremony in downtown Portland.

But in March 2015, The Oregonian/OregonLive reported that the Inspector General's Office began reviewing allegations that Marshall had constantly texted and emailed Assistant U.S. Attorney Scott M. Kerin.

Marshall took a leave of absence in March, citing health reasons that included post-traumatic stress disorder. She officially resigned on May 15, 2015, in the midst of the internal review.

"I sought intensive inpatient treatment and have spent every day since working on my recovery," Marshall said Tuesday. "My hope is that my family, Mr. Kerin's family, the USAO, DOJ, and the state can put this to rest and move on in our collective pursuit to do better today than we did yesterday."

Kerin reported the unwanted attention from Marshall to his immediate superiors, and they referred the matter to the inspector general. He remains on the job.

Kerin did not respond to an email seeking comment.

"Ms. Marshall acknowledges that when first confronted by DOJ about the affair, she denied the extent of their physical relationship in order to protect her and Mr. Kerin's privacy and dignity," Rhodes wrote. "She acknowledges the error of that decision and her decision to have an affair with a subordinate.

"In subsequent discussions she was completely forthright. Ms. Marshall fully cooperated with the OIG investigation," Rhodes wrote. "She did not intend to mislead anyone as to the subject matter of DOJ's questions nor the details of the relationship."

Colleagues recalled that at one point, Marshall, Kerin and their spouses had been social for a time. Marshall's husband is Yamhill County Circuit Judge Ladd Wiles and Kerin's wife is also a federal prosecutor in Oregon's U.S. Attorney's Office.

"Differences in perception exist anytime there is an affair that has occurred in a professional setting," Rhodes wrote. "We are accustomed to falls from grace by men in the profession and countless examples of inappropriate relationships in a government office. This case is only marked by the position of power of the woman in a relationship."

The inspector general's report noted that the findings will be forwarded to other Justice Department officials, including the Office of Professional Responsibility, to determine whether the conduct warrants referral to appropriate bar authorities.

Kateri Walsh, spokeswoman for the Oregon State Bar, said the agency hasn't received any complaints against Marshall. She also said the bar hasn't launched an independent investigation.

-- Laura Gunderson

503-221-8378; @lgunderson