Laurie Dann was born Laurie Wasserman on October 18, 1957, in Glencoe, Illinois, a suburb north of Chicago. She was the daughter of Edith Joy and Norman Wasserman, an accountant. The Wasserman family was Jewish, and Laurie had one older brother.

As a child, Laurie was described as shy and struggled to make friends. She showed signs of obsessive-compulsive disorder during her early years, but these behaviors seemed to disappear by the time she reached adolescence. In high school, she had a few brief romantic relationships. The family took a vacation to Hawaii in 1973, where Laurie met a boy named Barry Gallup. They dated after returning home, but Barry ended the relationship when he graduated and went to college.

In 1974, the Wassermans moved to a new neighborhood, which meant Laurie had to change high schools for her senior year. During a summer trip to Aspen, Colorado, she met another boy named Wade Keats, but that relationship also ended quickly. During her senior year, Laurie continued to date briefly and decided to undergo plastic surgery to make her nose smaller. She graduated from New Trier High School in 1975. Despite having poor grades, she was able to enroll at Drake University in Des Moines, Iowa. After a while, she transferred to the University of Arizona, initially intending to become a teacher, although she later expressed that her main goal was to find a husband.

While attending college, Laurie dated a pre-med student named Steve Witt. However, Steve was focused on his studies and did not give Laurie the attention she wanted. Their relationship ended when he moved on to a residency program in New York. During the summer of 1977, Laurie attended the University of Wisconsin in Madison for a course in home economics. After another failed relationship in 1980, Laurie moved back in with her parents. She transferred to Northwestern University to finish her degree but eventually dropped out of all classes and did not graduate.

After leaving school, Laurie worked as a cocktail waitress at a country club called Green Acres. Here, she met an insurance salesman named Russell Dann. Laurie embellished her background, claiming to be a graduate student and having an accounting degree. They dated for nine months and got married on September 11, 1982. Their honeymoon took place in the British Virgin Islands, but the marriage did not go well. Russell's family noticed Laurie's strange behavior, which included signs of her obsessive-compulsive disorder.

Laurie's relationships with family and friends began to deteriorate. She was often fired from jobs and would claim it was not her fault. She also began attending therapy but did not take it seriously, stopping and starting sessions multiple times. After Russell announced their separation, Laurie moved back with her parents, and her mental health worsened.

She began to make harassing phone calls to Russell and his family. In 1986, she accused him of various offenses, including breaking into her family home and abusing her. Despite receiving treatment for her mental health issues, she continued to show erratic behavior. Laurie's situation continued to escalate, leading to various incidents, including theft and threats against former acquaintances.

By 1988, Laurie was living in a university apartment, where her unusual actions became more pronounced, such as spending hours riding elevators. Following further treatment, her mental health challenges persisted. Eventually, she stopped attending her therapy sessions and continued to make threatening phone calls to those she knew.

On May 20, 1988, Laurie Dann delivered poisoned rice cereal snacks and juice boxes to various people, including her former babysitting clients and a psychiatrist. She also sent snacks to fraternity houses and other targets. Some snacks were leaking and tasted bad, so few people consumed them, leading to no serious illness.

Around 9 AM, Dann picked up two children from the Rushe family. Although she promised to take them to a fair, she instead went to a school. Leaving the children in the car, she entered the school and attempted to detonate an incendiary device. The small fire created was quickly extinguished by staff. She then drove to a Jewish daycare center but was stopped from entering with a can of gasoline.

She returned the children to the Rushe home and offered them poisoned milk, which they rejected due to the strange taste. Dann then lured them downstairs and set fire to the house, but the family managed to escape the flames. Next, she drove a short distance to Hubbard Woods Elementary School, armed with three handguns. She wandered around the school before pushing a six-year-old boy, Robert Tressmann, into a bathroom and shooting him in the chest.

Dann went back into a classroom where she ordered children to the corner and began shooting at them. She killed Nick Corwin, an eight-year-old boy, and injured several others before fleeing the school. As she attempted to escape, she crashed her car into a tree and abandoned it.

Dann sought refuge in a nearby house belonging to the Andrew family, claiming she had been raped and was being pursued by the police. While at the Andrew home, she shot Philip Andrew, the family's son. Shortly after, police surrounded the house, leading to an assault team entering later in the evening, where they found her dead from a self-inflicted gunshot wound.