PORTLAND – The state supreme court Monday denied a Limestone woman’s appeal of her murder conviction, saying the improper admission of testimony pointing to her violent character amounted to harmless error.

Laura Kirk, 36, is serving a 50-year sentence for the Dec. 16, 2001, stabbing death of Tara Bell, 27, a child-care provider, at her home in Caswell.

During the three-day trial, the prosecution said Bell and Kirk had both been going through divorces and that Kirk became angry and jealous of Bell, blaming her for the breakup of her own marriage.

The Supreme Judicial Court agreed that the trial judge erred in allowing testimony by Kirk’s ex-husband, Gerald Kirk, about an incident in which the defendant hurled a drinking glass that struck him in the face, requiring eight stitches.

Gerald Kirk’s testimony was offered as a rebuttal to cross-examination testimony by the defendant’s former stepfather regarding her nonviolent character.

The justices concluded that the error was harmless because the murder she was charged with involved conduct far different than throwing a glass at someone, and that other evidence linking Kirk to the killing was very strong.

The court said the defendant’s husband was having an affair with Bell, who provided day care for the Kirks’ children, and that Kirk blamed Bell for the fact that she and her husband could not get back together.

“Kirk confessed to friends of having ‘bad thoughts’ that could get her locked up for the rest of her life, of wanting to hurt Bell, and of fantasizing about hiding in Bell’s car and slitting Bell’s throat,” the opinion said.

Soon afterward, the court added, Bell was found dead in her home of multiple stab wounds.

The court went on to note that Kirk’s blood was found in Bell’s refrigerator, Kirk had a bruised forehead and cuts on her neck and hands, and bloody footprints found in Kirk’s van matched those found in Bell’s home after her death.

“The strength of that evidence leads us to conclude that it is highly probable that the jury did not convict Kirk of this brutal murder because she threw a glass at her husband seven years before the murder and nine years prior to trial,” the opinion said.