A chilling memoir written by the Minneapolis shooter while they were a student at a military-like school has been revealed in the aftermath of the slaughter which left two children dead on Wednesday.

Robin Westman, 23, wrote an ode to death titled 'But Not The End' in which they outlined concerns that they would die with 'regrets that my name not be known for something more', according to the Star Tribune.

The chilling note came from Westman's time as a pupil at St. Thomas Academy, a Catholic all-boys school in Mendota Heights, Minneapolis, where students are referred to as cadets, wear uniform and are trained in military skills.

It was one of several schools that Westman attended during a seemingly turbulent childhood where they went to one school for just three months, changed gender to female, and saw their parents divorce.

The cold-blooded killer used three guns to open fire on children as they prayed at Annunciation Catholic School - the institution Westman graduated from eighth grade in 2017, and where the suspect's mother worked as a parish secretary.