WASHINGTON – Threats against federal judges are on a record-setting pace this year, nearly 18 months after the family of a federal judge was killed in Chicago.

U.S. marshals, who protect the nation’s 2,200 federal judges, believe they averted another potential tragedy in the Midwest last year when they helped block the release of a prison inmate who told a judge in a series of sexually charged letters that he was going to take her away.

Threats and inappropriate communications have quadrupled over 10 years ago. There were 201 reported such incidents in the 1996 government spending year and 943 in the year that ended Sept. 30, 2005, Thomas Folan, the marshal in charge of judicial security for federal judges in Maine, said Monday.

This year alone, the Marshals Service has had 822 reports of inappropriate communications and threats, a pace that would top 1,000 for the year.

“We’ve had a couple of dozen threats in the past two or three years,” Folan said. “Some [threats] have been significant. Other people have just been venting. We consider all to be equally important and investigate them all.”

Federal judges in Maine receive fewer threats than those in more populous states, Folan said Monday from his Portland office. He investigates all inappropriate communications sent to the dozen judges, including the three who sit on the 1st Circuit Court of Appeals in Boston and live and work in Maine.

Marshals provide security for three federal magistrate judges, four district court judges and two bankruptcy court judges in Maine, according to Folan. That includes overseeing protection for judges when they travel on official business in and outside the U.S.

The Marshals Service in Maine also provides security for federal judges passing through or visiting the state, including U.S. Supreme Court Chief Justice John Roberts. Roberts and his wife, Jane Sullivan Roberts, earlier this year purchased a summer home on Hupper Island off Port Clyde.

A threat typically includes a direct reference to harm, a weapon, or a violent act. Inappropriate communications range from rambling letters to accusations of bias to envelopes that contain feces.

Marshals in Washington, D.C., say a portion of the increase can be attributed to a heightened focus by judges and their staffs since the February 2005 incident in which unemployed electrician Bart Ross broke into the home of U.S. District Judge Joan Lefkow and shot to death her husband and mother.

One judge targeted by an inmate who had appeared before her received, but had not opened, a dozen letters from the inmate over more than six months, said Michael Prout, chief inspector of the Marshals Service’s protective security division until last August.

Spurred by the Lefkow killings, the judge sent the unopened letters to marshals last year.

“The inmate had fixated on this judge and claimed her as his bride and described bizarre sex acts he was going to perform on her when he came to take her away,” said Prout, now the chief deputy marshal in Chicago. “He was going to take her away very shortly because he was getting out of jail.”

The inmate’s release date was three to four months away when the letters came to the attention of marshals, Prout said. He would not identify the judge or the city in which she serves.

But marshals say there was a steady upward trend of angry, inappropriate comments long before the shootings.

Supreme Court Justice Ruth Bader Ginsburg revealed in February that she and former Justice Sandra Day O’Connor were threatened a year ago by someone who called on the Internet for the immediate “patriotic” killing of the justices.

The rise in civil lawsuits, especially those filed by people who do not have lawyers, and a change in the kind of criminal cases in federal courts helps explain the rise, according to the marshals service.

Federal courts now handle many more violent crime prosecutions, the sorts of cases that were the province of state and local courts as recently as 10 years ago.

Threats directed at federal judges in Maine, according to Folan, are divided almost equally between civil and criminal cases. In general, the most serious threats arise from cases in bankruptcy court or from civil cases where large amounts of money are at stake, he said Monday.

Marshals say that even before the Chicago killings, they responded to every inappropriate communication, reasoning that they would be able to resolve a situation more quickly the earlier they interceded.

But in the aftermath of the Lefkow deaths, judges criticized the marshals under former director Benigno Reyna as insufficiently responsive to their security. A Justice Department inspector general’s report in 2004 also pointed out shortcomings in marshals’ assessments of threats. Reyna resigned last year.

John Clark, a career marshal named by President Bush to head the Marshals Service, has expanded the number of marshals trained to investigate threats and expects to open a 24-hour assessment and analysis center later this year.

Folan, who has worked for the Marshals Service in Maine for 16 years, now is working full time on judicial security. About 30 part-time court officers who work at the federal courthouses in Bangor and Portland report to him.

In Chicago, Prout said he is in regular contact with state and local counterparts to identify people who may be moving between courts at all levels, their frustration with the legal system rising.

The most notable change that grew out of last year’s killings was the decision by Congress to set aside $12 million to install security systems in judges’ homes.

About 1,700 judges, including a majority who live and work in Maine, have asked for the home alarms. Fewer than a third of those, about 500, have received them, Horton said.