A Superior Court judge ruled Tuesday that a 45-year-old woman charged with setting two major fires in Norwich last spring while on probation for a previous arson case is not competent to stand trial.

Judge Susan B. Handy ordered that Laura J. MacDonald, who had been held at the Janet S. York Correctional Institution in lieu of $700,000 bond since she was arrested in July, be sent to the Whiting Forensic Institute for 60 days. Clinicians at the state hospital for the criminally insane will attempt to restore MacDonald to competency so that she can stand trial.

"The defendant, Laura MacDonald, is incapable at this time of understanding the proceedings against her and is unable to assist in her defense," the judge said in a ruling from the bench.

MacDonald, an East Lyme native, has a history of mental illness and has accumulated a long list of diagnoses, including, most recently, schizoaffective disorder, drug and alcohol abuse, bulimia and borderline personality disorder. During a hearing Tuesday in New London, she sat quietly at the defense table while the officials discussed her mental health.

MacDonald had served 10 months in prison for reckless burning in connection with the Capehart Mill fire in April 2010. She was on probation when she allegedly joined with a group of younger people in March to set fire to homes on Oak and Lake streets. She was living in a Reliance House residence on the Uncas on Thames Campus at 401 W. Thames St. in Norwich that was to provide around-the-clock supervision.

MacDonald is charged with two counts each of first-degree arson, first-degree criminal mischief and third-degree burglary. Her attorney, Public Defender Bruce A. Sturman, in August asked for a competency evaluation of his client based on her history. She had been found incompetent and spent time at Whiting's restoration unit while her previous case was pending. She ultimately was found competent.

Clinical social worker Bruce Knox of the Connecticut Mental Health Center testified that he went to the women's prison Oct. 2 with a psychiatrist and psychologist to evaluate MacDonald. Knox said MacDonald was unable to stay focused during the interview and was "hit or miss" when asked about the court proceedings. He said that based on her history, there is "a substantial probability" that she can be restored to competency. He recommended 60 days of hospitalization.

Prosecutor David J. Smith noted that MacDonald had admitted to using K-2, a hallucinogenic drug, on two occasions while on probation. Knox said MacDonald's use illegal substances concerned the clinicians and led them to conclude that the state hospital was, in accordance with the law, the least restrictive setting for restoring MacDonald to competency.

She will return to court on Dec. 18, when the judge will listen to more testimony before determining whether MacDonald has been restored to competency.

k.florin@theday.com