Why the Confederate flag started trending after the Charleston shooting

The controversial Confederate flag flies outside of South Carolina's state house

UPDATE: It was reported later that suspect Dylann Roof drove a car with Confederate flag licence plates.

In the wake of the mass shooting in South Carolina, the image of the Confederate flag started trending online - driven by liberals who blame it for stoking racism in America.

As news broke of a mass shooting which killed nine in a church in Charleston in the state of South Carolina, a mostly predictable reaction developed online. But alongside trending phrases such as "Charleston shooting" and "Black lives matter", another term became a top US trend on Twitter: "Confederate".

It's a reference to the red and blue Confederate battle flag, which 150 years after the American Civil War is still flown outside South Carolina's state house. The flag has long been a contentious issue across the American south, where some see it as a symbol of slavery, racism and a failed breakaway nation, while others consider it an essential part of southern US heritage and an homage to freedom and military service. The debate sometimes - but not always - breaks down along racial lines. (Here's an essential primer on the flag controversy by the BBC's Tom Geoghegan.) In a measure of just how divisive the flag is, the Supreme Court ruled Thursday on a case involving whether the flag could be banned from customised car number plates in Texas.

In a matter of hours after the attack, more than 30,000 tweets were sent including the word "confederate" - the vast majority referring to events in South Carolina. On Twitter some liberals and civil rights activists went so far as to link the flag and South Carolina Governor Nikki Haley, a Republican who supports the flying of the banner, to the attack at the Emanuel African Methodist Episcopal Church.

"Maybe when y'all start asking 'why' tomorrow. The Governor can look at the Confederate flag flying over state capital," said Desiree Adaway. Al Jazeera columnist Chase Madar tweeted in reference to a statement released by Haley after the shooting: "Governor who flies Confederate flag at SC capitol says "we'll never understand what motivates" #Charleston massacre." Hundreds of messages called for the flag to be removed.

But others found the link baseless and worse. In response to a tweet mentioning the flag sent by a former government official, conservative radio presenter Dana Loesch commented: "How does this help? Are you accusing Nikki Haley? Absolutely classless." Another tweeter sarcastically commented: "[Someone] shoots up church killing 9 but it's the governor's fault bc a of 154 year old confederate flag that's 113 miles away. Makes sense."

Charleston police chief Gregory Mullen described the attack as a "hate crime" and on Thursday police said they arrested a suspect, 21-year-old Dylann Roof. Updates about the developing story can be found on this live page.

Blog by Mike Wendling

Next story: How video saved the calligraphy star

Some say that technology is killing off handwriting... but a new generation is using social media to keep the ancient, analogue art of calligraphy going strong in the digital world. READ MORE

You can follow BBC Trending on Twitter @BBCtrending, and find us on Facebook. All our stories are at bbc.com/trending.