In what could be a landmark ruling involving the use of the so-called battered woman syndrome defence, the Supreme Court of Canada heard arguments on Thursday about a case involving a Nova Scotia woman who tried to hire a hit man (who turned out to be an undercover RCMP officer) to kill her husband.

The woman, who claimed she had no other way out of an abusive relationship, was acquitted of counselling to commit murder. The following are cases where women killed their husbands and argued self-defence.

In what many consider the first battered woman syndrome defence in Canada, on April 16, 1911, Sault Ste. Marie resident Angelina Napolitano took an axe and killed her husband Pietro while he slept.

At her trial, Napolitano’s court-appointed lawyer argued that his client had been repeatedly abused by her husband and that he had stabbed her six months prior, according to the Dictionary of Canadian Biography Online.

But the judge ruled the evidence inadmissible, and Napolitano was found guilty. Although the jury recommended clemency, the judge sentenced her to hang.

Napolitano became a cause célèbre at the time, with many advocating her sentence be commuted. The federal cabinet did commute her sentence to life imprisonment, and she was granted parole 11 years later.

On March 9, 1977, Michigan housewife Francine Hughes poured gasoline around her husband's bed as he slept and set it on fire, killing him. Hughes, who had suffered from years of abuse, was found not guilty by reason of insanity. The case was chronicled in a book titled The Burning Bed and later made into a TV movie starring Farrah Fawcett.

In this landmark case, on Aug. 31, 1986, Manitoba resident Angelique Lyn Lavallee, 22, fatally shot her common law partner Kevin Rust in the back of the head as he left her room following a heated argument. Court heard that during their relationship, Lavallee was frequently abused by Rust.

A psychiatrist testified in her trial that she had been terrorized by Rust and that she felt trapped and unable to escape the relationship. He said that the shooting "was a final desperate act by a woman who sincerely believed that she would be killed that night," court heard.

Lavallee was acquitted by a jury of second-degree murder on the basis of self defence, but the verdict was overturned by a majority of the Manitoba Court of Appeal and the case sent back for retrial.

The case ultimately went to the Supreme Court, where the issue centred on whether the evidence of the psychiatrist should have been before the court.

The top court agreed that the evidence was pertinent, recognizing that battered woman syndrome is a legitimate defence.

On March 23, 1991, Margaret Ann Malott shot and killed her estranged common law husband Paul Malott at a medical centre. She then took a taxi to his girlfriend’s home and shot and stabbed her with a knife, although the girlfriend survived.

Court heard that Paul Malott had "physically, sexually, psychologically and emotionally" abused Margaret Ann Malott. She had complained to police, who then informed Paul Malott about the complaints because he was a police informant on drug deals, court heard.

Expert evidence showed she had suffered from battered woman syndrome, and the Crown conceded that she had suffered physical and mental abuse by Malott. She was found guilty of second-degree murder, but the jury recommended she receive the minimum sentence because of the severity of the abuse she'd suffered.

Malott appealed the sentence to the Supreme court but her appeal was dismissed.

Last year, Sheehan was acquitted of second-degree murder after having shot her husband, a retired police sergeant, 11 times in their New York home in 2008.

Sheehan testified that she had suffered repeated abuse during their relationship. The day she shot him, she said she had refused to go to Florida with him, angering him to the point that he threatened to kill her and pointed a gun at her head.

Hours later, while he shaved in her bathroom, she shot him, using two of his own guns.

Although cleared on the murder charge, she was found guilty of gun possession.