On Monday, yet another fatal shooting took place in the US, this time in Boulder, Colorado.
The incident took place at the The King Soopers store, about 25 miles northwest of the state’s capital Denver, and home to the University of Colorado.
The attack, which left 10 dead, including a police officer, marks the seventh mass killing in the US this year, following a shooting in Atlanta last week that left eight people dead.
Here is everything we know so far:
At around 14:30 local time (20:30 GMT), police received the first 911 calls after a suspect entered the supermarket and began firing.
Witnesses said they ran out of the building or hid as the shooting unfolded.
Sarah Moonshadow, a customer at the store, told Reuters she had tried to help a victim lying on the pavement outside the store, but her son– who she had been shopping with – pulled her away.
“We were at the checkout, and shots just started going off,” she said. “I couldn’t help anybody.”
Soon, authorities gathered outside the building and used a loudspeaker to shout “you need to surrender” at the suspect.
An hour long standoff ensued until officers escorted a shirtless bearded man out of the store with handcuffs. They did not confirm if he was the suspect.
Police have said the investigation is complex and that it will take at least five days to complete.
How many died?
In total, 10 people were killed by the gunman. The victims were aged between 20 and 65.
Who were the victims?
Among the dead was 51-year-old Eric Talley, the first police offer to respond to the shooting. He had been with the Boulder police force since 2010 and his father said he had been looking for a new job as a drone operator. His actions were “nothing short of heroic,” the Boulder police chief said.
The names of the other nine victims are: Denny Strong, Nevin Stanisic, Rikki Olds, Tralona Bartkowiak, Suzanne Fountain, Teri Leiker, Kevin Mahoney, Lynn Murray and Jody Waters.
Denny Strong was the youngest victim at just 20 years old and was training to be a pilot. He worked at King Soopers.
Who is the suspect?
Police have arrested a 21-year-old male suspect, Ahmad Al Aliwi Alissa. Officers have not revealed a suspected motive for the shooting. They said he was injured and was receiving medical care.
The suspect’s family told investigators they believed Alissa was suffering from a mental illness, and described occasions in which he had experienced paranoid delusions.
In 2018, while in high school, he was found guilty of assaulting a fellow student.
What has the reaction been?
Unsurprisingly, the event was met with shock and mourning. Boulder Country District Attorney Michael Dougherty said: “This is a tragedy and a nightmare for Boulder County.
“These were people going about their day, doing their shopping.
“I promise the victims and the people of the state of Colorado that we will secure justice.”
Meanwhile, Matthew Kirsch, the acting US attorney for Colorado, pledged that “the full weight of federal law enforcement” will support the investigation.
And at a press conference, Boulder police chief Maris Herold tried to placate the town’s concerns. “I want to reassure the community that they are safe,” she said.
Vice President Kamala Harris said the shooting was “absolutely baffling” and paid tribute to the victims who were “living their lives, not bothering anybody”.
Joe Biden called for a ban on assault weapons, following the attack, and said background check loopholes should be closed that are present when someone purchases a firearm.