It was a Wednesday morning in March, 1996, just after 9:30am, when eight-year-old Andy Murray – now one of the best tennis players to have ever lived – heard two gun shots outside his classroom at Dunblane Primary School.
The shots came from near the assembly hall in the small school, located in Stirlingshire, Scotland.
Murray never imagined the shots were being fired by someone he knew; 43-year-old former scout leader Thomas Hamilton.
In his autobiography Hitting Back, Murray says he attended a youth group run by Hamilton, who the family knew well enough to occasionally drive home.
But that day, Hamilton had on him 743 cartridges of ammunition – and would, over the next three to four minutes, become responsible for the deadliest mass shooting in British history.
The school day had only just begun when Hamilton entered the gymnasium, and shot at PE teacher Eileen Harrild, who was running a lesson. He then opened fire, injuring several students and teachers.
Gwen Major, a teacher of the class, was killed instantly.
Inside that gymnasium, Hamilton went on to fire some 35 shots, many at point blank range. The children he murdered were five and six years old.
Meanwhile, Murray and his older brother, Jamie, hid under desks in a nearby classroom. He recalls singing songs quietly, to drown out the noises.
Hamilton left dozens incapacitated in the gymnasium, and walked out the door towards the library. There, he shot at random, striking several more teachers and students.
He went on to enter a mobile classroom, where teacher Catherine Gordon ordered all the students to lie down as close as they could to the floor. Hamilton shot nine bullets, one which hit a chair where a student had been sitting only seconds before.
It was then that Hamilton reentered the gymnasium, where 16 lay murdered, and put the barrel of his gun to his own mouth.
The first call to police was made at 9:41am. Thirty two people were treated for gunshot wounds, and one child died en route to hospital.
Listen to True Crime Conversations, which this week explores the man behind the Dunblane Massacre. Post continues below.