Alberta is a wonderful place to live, but like everywhere else, it has its “dark side.” Calgary Yes shares stories of Alberta’s most notorious criminals whose crimes shocked the public. More on calgaryes.com.
The Cook Family Massacre
In 1959, Albertans were horrified by the murder of the Cook family. John Etter Clark was a teacher, provincial politician, farmer, and a member of Alberta’s Legislative Assembly. His career appeared successful, as did his personal life. He was married and had four children. However, this façade shattered when he committed one of Alberta’s deadliest mass murders.
In 1956, a neighbour discovered six bodies and one injured individual, who later died in the hospital. Following the grisly discovery, the Royal Canadian Mounted Police (RCMP) and special agents arrived at the scene. Among the dead were Clark’s wife, three daughters, one son, a hired worker, and another individual believed to be a guest of the family. The weapon used was a rifle. Two years earlier, Clark had been hospitalized after a nervous breakdown, and during the spring legislative session prior to the murders, he experienced another breakdown—with devastating consequences for his family.
Clark avoided legal punishment, as he took his own life in 1956 at the age of 41.
The Richardson Family Murders
This case occurred in 2006, when three members of the Richardson family were brutally killed by their 12-year-old daughter and her boyfriend. Jasmine Richardson and Jeremy Steinke (now Jackson May) carried out the murders using knives and were convicted of first-degree murder. Jasmine, who was 13 at the time of her sentencing, became the youngest person in Canada to be convicted of such a crime. She was released from a psychiatric hospital in 2016 after serving a 10-year sentence.
The Motive
What motivated such a crime? In April 2006, the bodies of Jasmine’s father, mother, and 8-year-old brother were discovered in their home’s basement. Jasmine was initially thought to be a missing victim, but she and her 23-year-old boyfriend were arrested the following day. A 19-year-old friend of the couple was also charged as an accomplice for helping them destroy evidence. Jasmine later admitted that her parents had forbidden her relationship with Jeremy due to the significant age difference, frequently criticizing their union. As for her 8-year-old brother, Jasmine claimed it would have been “cruel” to leave Jacob parentless, so they decided to kill him as well. After fleeing the scene, the couple attended a house party, bragging about their crime—a detail that ultimately led to their capture.
By September 2011, Richardson was attending classes at Calgary’s Mount Royal University. In 2012, she expressed remorse for her actions. Her boyfriend, however, will not be eligible for parole until 2033.
Mark Twitchell
Dubbed the “Dexter Killer” by the media, Mark Twitchell was an aspiring filmmaker who lured a man to his death, dismembering the body afterward. Twitchell used a fake online dating profile to ensnare his victim. What made this case even more chilling was a document discovered on Twitchell’s laptop, where he detailed his transformation into a serial killer. The document outlined his planning, the act of dismemberment, and other gruesome details.
After Twitchell’s arrest, law enforcement uncovered that he had been inspired by the fictional character Dexter Morgan from the popular television series—a cold, calculated sociopath. Twitchell sought to create his own “short thriller,” based on real-life events, with himself starring as the cold-blooded murderer.
Twitchell was convicted in April 2011 for the murder of Johnny Brian Altinger, whom he had lured to a “kill room” in 2008. The case captured widespread media attention, with the public horrified by every new detail of this grim crime.
Clifford Sleigh
This is a horrifying story of abduction, assault, and murder. In 1992, Clifford Sleigh kidnapped, raped, and killed a young girl. However, Sleigh remained free for 11 years before his arrest in 2003. Previously, Sleigh had been convicted of sexually assaulting two other young girls. Six-year-old Corrine “Punky” Gustavson’s body was discovered two days after her disappearance in a truck yard. Investigations revealed that she had suffered sexual assault before being strangled.
Sleigh later told police he had been angry at his common-law wife and drove around looking for someone to harm. Spotting the girl playing with her friend, he chose her because she was closest to the fence. He was sentenced to life imprisonment without the possibility of parole for 25 years. At his sentencing, the then-42-year-old Sleigh broke down in tears, apologizing to Corrine’s family, but the trauma for her loved ones remained immeasurable. Corrine’s parents described how her death devastated their lives—her father suffered a nervous breakdown, leading to the couple’s separation. Her mother struggled to cope with the loss, unable to witness her daughter grow up, learn, or start her own family.
Derek Jensen
This case involved the murder of two young men and a woman, with jealousy believed to be the primary motive. Derek Jensen had previously dated one of the victims, Tabitha Stepple, and witnesses reported him threatening her at a party, saying, “This won’t end well for you.” Later, Jensen saw Tabitha with her friends at a convenience store in Calgary. Overcome by rage, he rammed his car into their vehicle, approached them, and shot all four individuals. Jensen then took his own life.
Among the deceased were Tanner Craswell, 22, and Mitch MacLean, 20—teammates and best friends with promising futures in baseball. Tabitha Stepple also lost her life. Shaina Conway was the sole survivor, recovering after hospitalization.
Travis Baumgartner
A former armoured car guard, Travis Baumgartner gained notoriety in 2012 for killing three colleagues and seriously injuring another during a robbery at the University of Alberta campus. At the time, Baumgartner was only 22 years old. He was arrested at the U.S. border in British Columbia and sentenced to life in prison with no possibility of parole for 40 years. This sentence was Canada’s harshest since Arthur Lucas was executed in 1962 for the murder of a police informant.
These chilling crimes remain dark chapters in Alberta’s history. While they are among the most shocking, they are not the only crimes to have left an indelible mark on the province.