The shooting occurred around 3:15 p.m. inside an Annapolis, Maryland, building that houses the offices of Capital Gazette Communications, which also publishes other community publications, including the Capital and the Maryland Gazette.
Jarrod Ramos, 38, was arrested and charged with five counts of first-degree murder. He had unsuccessfully attempted to sue the paper for defamation in 2012.
Many journalists and others took to social media to offer their support and share stories about what they described as a small, "tight knit" newsroom committed to local news.
Here's what people are saying about the Capital Gazette:
Justin Fenton, a reporter for the Baltimore Sun, said he delivered the Capital as a boy and that the newspaper was "on the dinner table every night" when he was growing up.
Another Sun reporter, Erin Cox, said the newsroom was "a tight knit family" and "deeply devoted to the mission of community news."
Meredith Newman, who previously worked for the Annapolis paper, described its newsroom as "scrappy," saying it is "made up of reporters who are constantly keeping elected officials accountable and telling stories of those in the community."
Jenna Johnson, a correspondent for the Washington Post, said the newsroom "has always produced great coverage with a small staff."
McClatchy reporter Josh Magness said he grew up reading the Annapolis newspaper and interned there.
The US Naval Academy, which is based in Annapolis, called it "our local newspaper" and "the first to tell our story."
And despite Thursday's tragedy, reporters, photographers, and other news staffers still carried on with doing their jobs.
"We are putting out a damn paper tomorrow."
In fact, in response to what officials said was a targeted attack, journalists and others rallied behind a call to support the Capital Gazette by subscribing.
The Associated Press Media Editors group also pledged to assist the Capital Gazette as its staff recovers from the attack, and called on other news organizations to do so in the days ahead.