A series of sexually charged allegations over the past year, including a recent claim by a prostitute that Chief U.S. District Judge Edward W. Nottingham Jr. had asked her to mislead judicial investigators about their weekly trysts, prompted Nottingham to resign his lifetime commission Tuesday.

“He is deeply remorseful for his actions,” Nottingham’s lawyer wrote in a public statement that didn’t specify exactly what those actions were or whether any of the publicized anonymous claims are true. “He is also embarrassed and ashamed for any loss of confidence caused by those actions and attendant publicity and sincerely apologizes to the public and the judiciary.”

Nottingham submitted his resignation to President Bush and said it had become clear that leaving the bench was the only way to put the matter behind both him and the court where he had worked for almost 19 years.

The resignation came as Chief Judge Robert Henry of the 10th U.S. Circuit Court of Appeals was in the midst of investigating Nottingham for misconduct.

Henry, in a statement of his own, acknowledged for the first time the breadth of the investigation, which began last fall after a complaint arose from testimony in Nottingham’s divorce case about how he spent thousands of dollars in one night at a Denver strip club.

Since that initial complaint, 9News has reported that Nottingham’s name emerged as a client in an investigation of a Denver prostitution ring and that a prostitute had complained to the 10th Circuit that Nottingham had asked her to mislead judicial investigators about their relationship. The prostitute’s identity remains secret.

“The Judicial Council, through its appointed special committees, conducted a thorough and extensive investigation, interviewed many witnesses, considered voluminous documentation and conducted two hearings,” Henry wrote in a statement issued Tuesday. “At this critical time in the investigation of these multiple complaints of misconduct, Judge Nottingham has stepped down, effective immediately, as chief judge of the district of Colorado, has ceased judicial duties and has resigned his commission as a United States district judge effective Wednesday, Oct. 29, 2008.”

Nottingham left the bench last week, turning a drug trial over to another judge, and has not been in court this week.

Jeff Dorschner, spokesman for the U.S. attorney’s office in Colorado, said he could not comment on whether a criminal investigation into Nottingham’s conduct is underway.

Nottingham’s resignation won’t have a serious impact on criminal cases pending before the court, though it could result in some minor delays, Dorsch ner said.

A statement from the U.S. District Court for Colorado said that Judge Wiley Y. Daniel would step up to become chief judge, overseeing the operation of the courthouse and the bench.

Daniel becomes the first African-American judge to be appointed chief judge at the U.S. District Court of Colorado.

In the statement on behalf of the court, Nottingham’s colleagues lauded his leadership, particularly in advancing technology and including electronic courtroom evidence presentation and case filings.

“Throughout his judicial career, Judge Nottingham worked tirelessly to ensure that his courtroom and case- management practices were premised on the law and applied fairly to all who appeared before him,” the statement said.

After working as a judicial clerk, private attorney and a federal prosecutor, Nottingham was appointed to the bench Nov. 27, 1989, by President George H.W. Bush.

His resignation, which had been rumored since last week, was largely greeted with consternation in the courthouse Tuesday afternoon.

Senior U.S. District Judge John Kane Jr., a Nottingham friend and one of just a handful of people willing to speak publicly after the resignation was announced, said he would continue to support him.

“I think now is the time when he needs his friends the most,” Kane said. “He was a hard-working, highly intelligent, dedicated judge. From what I now know, I think he made the best decision for himself and for the court to resign. I’m very saddened. It’s the destruction of a highly capable judge. But the court is an institution, not a group of individuals, and it will survive.”

Even U.S. Sen. Ken Salazar, who had sought Nottingham’s resignation, applauded his tenure on Tuesday.

“On the bench, Chief Judge Edward Nottingham was one of the most skillful lawyers and jurists I have known,” Salazar said. “I am saddened by the allegations and it is right that he resign. He has done what is in the best interest of the United States District Court for Colorado.”

Federal judgeships are lifetime appointments. Judges leave the bench only through resignation, retirement, death or impeachment.

In the past five years, approximately 12 federal judges nationwide have resigned without retiring, none of them in the midst of scandal. Almost all went into private practice or academia, typically for greater pay than the roughly $165,000 that district court judges earn.

Although two new judges were recently appointed by the president and confirmed by the Senate to replace other departed judges in Colorado, Nottingham’s resignation will leave the local federal bench further shorthanded.

The next president will select a replacement.

Meanwhile, Henry suggested that he may have more to say next Wednesday when the resignation becomes official.

A report by an independent investigator hired by the 10th Circuit is said to be complete, though details remain secret.

Staff writer Mike McPhee and researcher Barbara Hudson contributed to this report.

Felisa Cardona: 303-954-1219 or fcardona@denverpost.com