Martin Peyerl was born on August 11, 1983, in Bad Reichenhall, Bavaria, West Germany. He was the younger of two children born to Rudolf and Theresa Peyerl. His father was a former Bundeswehr (German Army) soldier and an avid gun collector who legally owned several firearms—up to nineteen according to investigators. The family lived in a modest home on Riedelstraße 12, and neighbors generally regarded them as quiet and reserved.

Peyerl’s childhood was marked by social isolation and academic difficulties. Classmates described him as shy, introverted, and largely ignored at school. While some said he was polite and “always nice,” others noted that he showed early signs of fascination with violence and firearms. His father frequently took him to practice shooting in the garage and to local forests where they hunted small animals, an activity that fueled his growing obsession with weapons.

During his teenage years, Peyerl’s behavior became increasingly withdrawn. He was temporarily suspended from school after being caught pasting Nazi-related photographs into his notebook. Investigators later discovered that he had painted swastikas and other right-wing extremist symbols in his bedroom, though criminologists later argued that his interest in neo-Nazi imagery was more about personal empowerment than political ideology. He reportedly had few friends, spent most of his time playing violent video games, and occasionally expressed admiration for mass shooters. After the Columbine High School massacre in April 1999, Peyerl reportedly remarked to classmates that “it was completely crazy what those guys did,” adding that it was “something we should do.”

At the time of the killings, Peyerl was working as a locksmith apprentice and still living at home. Though his family had financial difficulties and his father was described as frequently unemployed and alcoholic, there was no indication of imminent danger before the tragedy occurred.

On 1 November 1999, Martin Peyerl's parents left home to visit a grave, and he chose to stay behind. While they were gone, he accessed his father's gun cabinet and took a Ruger Mini-14. Around noon, his sister, Daniela, came home from work. A struggle occurred between them, and Martin shot Daniela five times, killing her.

Afterward, Martin took position at his bedroom window and began shooting at people outside. He killed two neighbors, 59-year-old Ruth Zillenbiller and 60-year-old Horst Zillenbiller. He also shot 54-year-old Karl-Heinz Lietz, who was a patient at the hospital across the street. In total, seven others were injured, including an actor named Günter Lamprecht.

Following the shootings, Martin shot his family cat and then turned a shotgun on himself, taking his own life in the bathtub.

When the police arrived at the house at around 6 PM, they found the bodies of both siblings and the cat. In Martin's room, they discovered swastikas and other Nazi symbols painted on the walls, as well as videos and CDs containing violent content.

The incident led to calls for changes in firearm legislation in Germany. The police interviewed Martin's parents as part of their investigation. Although there were discussions about possible motives, the head of the investigation stated that drugs, alcohol, or ideology were not factors. He suggested the issues lay within Martin's personality. Martin’s actions were viewed as planned, rather than spontaneous, although he left no clear explanation behind.