Police are calling the shooting deaths of six adults and two children in Edmonton "an extreme case of domestic violence gone awry" and the city's worst mass murder since 1956.

On Dec. 29, police discovered the bodies of the adults, ages 25 to 50, and the children, both younger than 10, at two homes in the city. They found the suspected gunman dead in a restaurant the next morning.

Below are some of the deadliest family murders in recent decades.

1956: Alberta MLA kills wife, 4 kids and farm hand

John Etter Clark, who served as a member of the Legislative Assembly of Alberta for four years, shot and killed his wife, son, three daughters and a family farm employee in 1956. Clark, who had been suffering from frequent nervous breakdowns for several years, then killed himself.

1959: Son kills dad, stepmom and their 5 kids

Robert Raymond Cook was the last person to be hanged in Alberta after killing his father, his father's new wife and their five kids through a combination of beating them with a shotgun and shooting them. The kids were between three and nine years old.

Police found their bodies in a pit in the garage covered with stuff.

Cook always denied killing his family, according to the Edmonton Journal, and stated his innocence after hearing the guilty verdict at his first trial. He appealed that conviction, but was found guilty in a subsequent trial as well.

He escaped from a hospital where he was being held after he learned he would not be permitted to attend the victims' funerals. Police found him four days later.

His tale was later incorporated into a fictional short story in Betty Jane Hegerat's The Boy.

1965: Vancouver cop kills wife, 6 kids after suspected robberies

A Vancouver police constable killed his wife and six children early one April morning in 1965. Leonard Hogue first shot his wife while she slept and then walked through his house, one-by-one killing his six children aged three to 13.

After committing the murders, Hogue shot and killed himself. Police suspect Hogue was an accomplice in two recent robberies. Some accomplices had recently been arrested, and police believe Hogue may have feared his arrest was imminent, according to Vancouver Sun archives.

1995-96: Serial murderer may have also killed 3 in India

Sukhwinder Singh Dhillon killed his wife and business associate to cash in on their insurance claims. He killed his wife, Parvesh Kaur Dhillon, in Hamilton, Ont., in 1995, and his business partner the following year, according to a Hamilton Spectator investigation into the serial murderer.

It is believed he married three other women in between the murders and killed his second wife and two male babies from the first wife. His weapon of choice was poison.

He was sentenced to life in prison for the deaths of Dhillon and his business partner, and died while serving his life sentence in Peterborough, Ont. He was 54 years old.

1996: Estranged husband kills 9 at sister-in-law's wedding preparation

In April 1996, Mark Chahal entered his former home in Vernon, B.C., while his estranged wife and her relatives prepared for her sister's wedding. He shot and killed his wife, Rajwar Gakhal, her sister and seven of her relatives.

Chahal then shot himself at a nearby motel.

Gakhal had previously filed formal complaints against her estranged husband with the RCMP, but nothing was done about them.

1997: Common-law husband murders wife, 4 kids with axe

It took police 24 hours to track down David John Gorton at a Vancouver Island motel after he killed his common-law wife and her four kids with an axe. Her four children were between two-and-a-half and 12 years old.

A judge sentenced him to life in prison with no chance of parole for 25 years.

2006: Teen girl helps boyfriend murder parents, brother

A 12-year-old girl and her 23-year-old boyfriend, Jeremy Steinke, killed her parents and brother by stabbing them repeatedly in 2006.

The pair allegedly murdered the family because they did not approve of their relationship. 

Steinke broke into the family's home and stabbed the mother 12 times and the father 24 times, according to expert testimony. The girl's eight-year-old brother suffered four stab wounds and a severed jugular vein. The girl testified that she stabbed her brother once at Steinke's request and claimed she was only joking during prior plans with her boyfriend to kill her family.

The girl was found guilty of three counts of first-degree murder and started her 10-year sentence at a psychiatric hospital. She was released from the hospital in 2011 and began reintegrating into the community, which included living in a group home and studying at a post-secondary institution.

The girl cannot be named under the Youth Criminal Justice Act because of her age at the time of the killings.

Steinke was sentenced to life in prison.

2009: Family kills daughters, wife over 'twisted concept of honour'

A Montreal couple, Mohammad Shafia and Tooba Yahya, and their son, Hamed, were charged with first-degree murder after the Shafia sisters and Shafia's first wife were found dead in a submerged car in Kingston, Ont. The sisters were between 13 and 19 years old.

At the trial, the Crown claimed the family planned a road trip as part of a plot to kill the four women because they had tainted the family's honour. That was partly because the two eldest daughters wanted permission to date.

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Mohammad Shafia, left, Tooba Yahya, centre, and their son Hamed, left, were found guilty of first-degree murder in the deaths of four women in the family believed to have been killed over tainting the family's honour.

The two eldest daughters had previously reported incidents of threats of violence from their father and brother to authorities. 

A jury sentenced the trio to life in prison with no chance of parole for 25 years.

"The apparent reason behind these cold-blooded, shameful murders was that the four completely innocent victims offended your completely twisted concept of honour ... that has absolutely no place in any civilized society," the judge said at the sentencing.

2013: Deportation fears drove murder-suicide

A couple and their 21-year-old daughter with cerebral palsy died in a murder-suicide in London, Ont., in the fall of 2013.

The London Free Press reported that the family's immigration status was unclear, but they were required to report in person to immigration officials monthly. The father's sister, Ruby Walji, told the London Free Press that the couple was exhausted after battling Immigration Canada for 15 years. A nurse who worked with the family said they feared deportation.

2014: Man kills wife, 2 sons who fled past abuse

Yusuf Osman Abdille killed his wife and two sons in a Toronto high-rise where they lived before jumping off a bridge onto the Don Valley Parkway to kill himself in December 2014.

Zahra Mohamoud Abdille and her sons, 13-year-old Faris and eight-year-old Zain, had fled her husband last year and lived for several weeks at a shelter for abused women and their families. During that time, Zahra failed to gain custody of her kids and did not qualify for affordable housing because of her income as a Toronto public health nurse.

She and her kids returned to live with her husband.