A Massachusetts judge was just doing her job when she freed a convicted killer now charged with murdering a newlywed couple, the chief judge of the state Superior Court said Monday in a case that has become enmeshed in the presidential campaign.

Republican Rudy Giuliani has cited the case to criticize former Massachusetts Gov. Mitt Romney's record on crime. Romney, who appointed the judge, has called on her to resign.

On Monday, Chief Justice Barbara Rouse said Judge Kathe Tuttman applied the law to the facts that were before her when she made the decision to free Daniel Tavares Jr.

"Today, unfortunately, she is living every judge's nightmare: that a principled decision based on the law and the information provided to her was followed by tragic events over which she had no control," Rouse said.

In June, Tavares completed a 16-year sentence for manslaughter for killing his mother, but prosecutors tried to keep him in prison for alleged assaults on two prison guards.

A district court judge approved bail of $50,000, but in July Tuttman overturned the decision and freed Tavares on personal recognizance. Tavares, 41, fled to Graham, Wash., and was arrested last week and charged with shooting to death Brian Mauck, 30, and Beverly Mauck, 28, who lived near him.

While still incarcerated in Massachusetts, Tavares threatened to kill Romney and other state officials in a letter that was intercepted by prison officials in February 2006, Romney spokesman Eric Fehrnstrom said. Massachusetts State Police suspected Tavares might be living in Washington state and, based on the earlier threat, warned Romney before his campaign appearance there last week, Fehrnstrom said.

In response to Rouse's defense of Tuttman, Fehrnstrom said in an e-mail: "Gov. Romney appointed Judge Tuttman based on her long record both as a prosecutor and as an advocate for victims. Judge Tuttman's entire experience as a prosecutor suggested she would be a law and order judge. Her actions in this case are inexcusable."

During the hearing before Tuttman, prosecutors underscored Tavares' history of violence and asked that if he were to be released, he be monitored with a GPS device.

Tuttman declined to order a monitoring system, saying she was presented with no evidence that he was a flight risk. She ordered him freed on the condition that he call probation officers three times a week, live with his sister and work.