It took just 17 minutes for the lives of the students and teachers at Covenant School in Nashville to change forever.
That was the time from when Audrey Hale, armed with two assault rifles and a pistol, shot their way into the school until they were gunned down by police.
In those few minutes between they killed six people including three nine-year-old children.
Although 10.10am on Monday March 27 was the moment the shooting spree really began, evidence suggests the 28-year-old put a lot of planning into it.
Police searched Hale's house and found a detailed map of the school, including potential entry points, and evidence they had clearly done surveillance before the shooting.
Hale was transgender and used male pronouns. Nashville police chief John Drake identified them as a transgender woman on Monday, in what appears to have been an error. A police spokesperson then told the Washington Post that Hale "is a biological woman who, on a social media profile, used male pronouns".
The killer had even written a manifesto which was later found by police.
The three children killed were Evelyn Dieckhaus, Hallie Scruggs and William Kinney, all nine-years-old.
The adults killed were identified as Cynthia Peak, 61, a substitute teacher, Mike Hill, 61, a janitor, and Katherine Koonce, 60, who was the head of the school.
Here is the timeline of the shooting.
9.53am - Hale arrives at the school in their car
In CCTV footage released by police, Hale's grey Honda Fit can be seen arriving at The Covenant School.
Hale drives past an unsuspecting person going about their day.
9.54am - The shooter finds somewhere to park
Hale drives past multiple free parking spaces, calmly looking for somewhere to leave their car.
Police later used the car to identify the shooter.
Releasing a picture of the car, a police spokesperson said: "Active shooter Audrey Elizabeth Hale, 28, drove this Honda Fit to the Covenant Church/school campus this morning and parked. MNPD detectives searched it and found additional material written by Hale."
9.57am - Hale messages a friend
Hale, 28, messaged their friend Averianna Patton on Instagram at 9.57am.
The shooter told Ms Patton "this is my last goodbye" as they explained she would soon be reading about their death "on the news".
“One day this will make more sense,” Hale wrote.
“I’ve left behind more than enough evidence behind. But something bad is about to happen.”
Ms Patton told NewsChannel5 tried to talk Hale down but the shooter responded: "I'm not trying to upset you or get attention. I just need to die."
A panicked Ms Patton called a Suicide Prevention Help Line at 10.08am after being told to by her dad.
If you or someone you know needs help, please call the National Suicide Prevention Lifeline at 1-800-273-8255.
10.10am - The shooting begins
In the minutes after parking up and messaging Ms Patton, Hale prepared for the planned attack on the school.
Hale is seen at 10.10am approaching a side door of the school and, barely pausing, shoots multiple rounds through the two double glass doors.
They kick their way through the remaining shards of glass before stepping into the school.
By this stage Hale is holding an assault rifle and has another on a sling over their shoulder.
They also appear to be wearing some kind of tactical vest.
10.13am - Hale stalks the halls as first 911 calls start coming through
With the assault rifle aiming from their shoulder, Hale walks through the carpeted halls of the school.
They are wearing a red cap on backwards, a white t-shirt, camo trousers and trainers.
At this point the first calls to 911 come through about shots being fired in the school.
Ms Patton also called the Nashville Davidson County Sheriff's Office at this time to let them know about the alarming messages she received from Hale but was told to call Nashville's non-emergency number.
"I called Nashville's non-emergency line at 10.14am and was on hold for nearly seven minutes before speaking with someone who said that they would send an officer to my home. An officer did not come to my home until 3.29pm," Patton said.
10.18am - Hale continues to search the school
Hale can be seen on CCTV returning to the same corridor they were hunting through before.
They seem unsure where they should be going and the rifle is no longer at their shoulder but held more casually beneath their arm.
10.19am - The shooter retraces their steps
The 28-year-old returns through the door they had just gone through and aims their gun in two directions although no one is there.
They try another door but returns 30 seconds later before going through a large fire door.
10.20am - Hale searches a new part of the school
As the shooter stalks through a brightly lit corridor they briefly look towards a passageway with the large words 'Children's Ministry' above it.
Towards the end of the footage, Hale can be seen putting the rifle to their shoulder and firing a shot. A small wisp of smoke is seen coming from the gun.
10.27am - Hale is shot dead by the police
Having shot at police as they arrived at the scene, a five man team of officers entered the building to put a stop to Hale.
On the second floor of the school, the shooter opened fire on officers who shot back killing them.
Seven people including Hale lost their life in the shooting.
The school community, the city and the country grieves for the latest in a long line of school shootings.
