Roger Girerd lived in Charvieu-Chavagneux, France, where he worked at a local foundry and also helped run the family farm. He was reportedly overworked, often laboring from early morning until evening. His mother pressured him to take on the hardest physical tasks, and he became mentally and physically exhausted over the years.

In 1959, due to his declining mental health, Girerd was committed to a psychiatric institution in Grenoble for several months. After being released, his condition seemed to improve, but by 1965, his behavior grew increasingly unstable. He expressed paranoia about an impending nuclear war, and became deeply fearful for the future of his children.

On the night of May 19, 1965, at the age of 34, Roger Girerd committed one of the deadliest familial massacres in French history. He began by stabbing his wife, Jeannette, and their six children, aged between 6 months and 10 years, as well as his 16-month-old niece, Sylviane Gonnet. The bodies of Jeannette, four of his children, and his niece were found the next day in the kitchen, covered with sheets, while the two remaining children were discovered on the first floor. Around 8:30 a.m. on May 20, a witness heard two gunshots from the farm; it was believed that Girerd then shot his 58-year-old mother, Angèle, and his 23-year-old brother, Robert, in an annex. Approximately 90 minutes later, two more shots were heard—Girerd had killed his dog and then himself.

In a suicide note, Girerd expressed his despair over living in poverty and his desire to prevent his children from enduring the same hardships. He wrote: 
"I have enough. I have to do something. I don't want my children to have to live the way I have to. I want everyone to live in peace. ... I am leaving money for the funeral and to pay my debts."

The victims of this tragic event were:

1. Jeannette Girerd, 34, wife
2. Eliane Girerd, 10, daughter
3. Joceline Girerd, 8, daughter
4. Bernard Girerd, 7, son
5. Yves Girerd, 4, son
6. Daniel Girerd, 2, son
7. Pierre Girerd, 6 months, son
8. Sylviane Gonnet, 16 months, niece
9. Angèle Girerd, 58, mother
10. Robert Girerd, 23, brother

This case remains one of the most harrowing instances of familicide in France, highlighting the devastating impact of mental health issues and societal pressures.