In a few short minutes a disgruntled employee armed with an AR-15 rifle fatally shot five colleagues at the Old National Bank in Louisville, Kentucky, before himself being gunned down by police.
The shooter was later identified as 25-year-old Connor Sturgeon, who had worked at the bank for years, first as an intern but reportedly knew he was about to be sacked.
Six people were killed, including the shooter, with nine being taken to hospital for treatment.
The five victims have been identified as Joshua Barrick, 40, Thomas Elliot, 63, Juliana Farmer, 45, James Tutt, 64, and Deana Eckert, 57.
Here is the timeline of the shooting.
Sturgeon leaves a note for loved ones
Sturgeon wrote a note to loved ones before going to the bank, a law enforcement source familiar with the investigation said.
The note to Sturgeon's parents and a friend said he was going to open fire in the bank.
It is not clear whether it was read before the incident or whether it was physical note.
According to a dispatcher dealing with the shooting, Sturgeon called a friend before the attack and left a voicemail saying that he felt suicidal and planned to "kill everyone at the bank".
Ominous posts on Instagram
In the minutes before bullets started flying, Sturgeon made a number of posts on his now deleted Instagram account.
One said: "They won't listen to words or protests. Let's see if they hear this."
Others included memes from movies such as Star Wars and Office Space.
The shooter went on to live stream the shooting on Instagram.
8.30am: The gunman opens fire
Police have said Sturgeon opened fire at around 8.30am.
Rebecca Buchheit-Sims, a manager at the Old National Bank, had logged on to a Microsoft Teams meeting when the shooting started.
She said: “Shortly after the meeting started, the gunman, which is an employee, started shooting up the conference room.”
Troy Haste, an account executive with Old National Bank, said he was in the conference room when Sturgeon opened fire.
"We heard a click, and the lady next to me turned around and said 'What the heck' and he just started shooting," Haste told WHAS.
While speaking to reporters he had someone else's blood on his shirt.
He said: "Whoever's next to me got shot, blood is on me from it."
8.38am: Police receive reports of shots fired
The first 911 calls start coming in that a shooting was underway.
Officers start rushing to the scene at 333 East Main Street in Louisville, Kentucky.
8:41am: Officers arrive at the scene
Armed police arrive at the scene.
Gunman Connor Sturgeon was still shooting when officers arrived and shots were exchanged.
Sturgeon is killed in a hail of police bullets but two officers are also injured.
One of the officers was newly recruited Nickolas Wilt, 26, who had recently graduated and been sworn into the force.
He was hit in the head by one of Sturgeon's bullets as he ran towards the mass shooter.
Officer Wilt was subsequently rushed to hospital where he underwent brain surgery. He remains in critical condition.
LMPD tweeted: “Officer Nickolas Wilt, a new officer to the LMPD, ran towards the gunfire today to save lives. He remains in critical condition after being shot in the head.”
It added the following tweet, confirming that Wilt had been the officer who stopped Sturgeon: “The name of our Officer who was critically wounded while stopping the active shooter: Officer Nickolas Wilt, a new officer to the LMPD recently sworn in.”
10am: No longer an active shooter
Police secure the scene and make sure there are no other shooters.
An update from the LMPD reads: "The lone shooter is deceased."
Despite this the public are advised to avoid the area.
At 10.12am Governor Andy Beshear arrives at the staging area at Louisville Slugger Field by the scene.
10.30am: LMPD Deputy Chief confirms five dead
In the initial press conference LMPD Deputy Chief Col. Paul Humphrey confirms that five people including the shooter had died with another six rushed to hospital. At that stage their conditions were unknown.
The figure of five dead was later updated to six when it was confirmed Deana Eckert, 57, had succumbed to their injuries.
The number of injured was also later updated.
11am: Another shooting nearby and more details emerge
Within hours police were called to a second fatal shooting nearby.
At 11am, officers rushed to Jefferson Community and Technical College in Louisville following reports about a shooting outside of the school.
One man was fatally shot and one was wounded.
The shootings are not believed to be connected, police said.
The shooter or shooters fled the scene and investigations continue.
At the scene of the mass shooting, police confirm a LMPD officer was in critical condition after being shot by the gunman.
It is also revealed that the gunman worked at the bank.
1.49pm: Investigators search a Louisville home
Authorities are seen searching a home on nearby Taylor Avenue in relation to the shooting.
The identity of the gunman has still not been revealed at this stage.
3pm: Connor Sturgeon, 25, identified as the shooter by authorities
In a police conference, the shooter is IDed as 25-year-old Connor Sturgeon who had worked at the bank.
This kicked off a frenzy of information being revealed about the shooter including his apparent history of struggles with mental illness.
At this stage police have not released his motive.
