(CNN) Before he stormed into the Capital Gazette newsroom in Maryland and killed five people, suspected gunman Jarrod W. Ramos first barricaded the paper's back entrance, authorities say.
Then he started "systematically hunting and killing" people with a shotgun he hid as he was entering the building in downtown Annapolis, Anne Arundel County State's Attorney Wes Adams said Friday.
The Thursday attack left five people dead: Gerald Fischman, 61; Rob Hiaasen, 59; John McNamara, 56; Rebecca Smith, 34; and Wendi Winters, 65. Two other employees were wounded in the shooting and have been released from the hospital.
Ramos allegedly used a 12-gauge pump-action shotgun and was carrying smoke grenades during the attack.
His motive remains unclear because he hasn't cooperated with investigators, but Anne Arundel County police Chief Timothy Altomare described it as a " targeted attack."
The first blasts came through the front door, sending employees rushing toward the back door. Ramos shot at least one victim who was trying to escape through the barricaded door, Adams said.
He was going up and down the newsroom, continually shooting people, police reporter Phil Davis said.
"There is nothing more terrifying than hearing multiple people get shot while you're under your desk and then hear the gunman reload," Davis tweeted
When police arrived, they found Ramos hiding under a desk. He has been charged with five counts of first-degree murder, according to court records. A judge ordered him held without bail.
"We are heartbroken, devastated. Our colleagues and friends are gone. No matter how deep our loss is nothing compared to the grief our friends' families are feeling," Capital editor Rick Hutzell said in the newspaper's front-page story on Friday.
The opinion page in Friday's paper was left mostly blank with a brief message: "Today, we are speechless. This page is intentionally left blank today to commemorate victims of Thursday's shootings at our office." It listed the five victims' names.
For years, the suspect had expressed his hostility against the paper in a lawsuit and in social media.
Court documents show Ramos filed a defamation suit in 2012 against the paper and a reporter over an article that detailed his guilty plea in a harassment case.
Titled "Jarrod wants to be your friend," the story written by staff writer Eric Hartley detailed how Ramos repeatedly contacted a former high school classmate via Facebook, according to court documents.
The case was eventually dismissed.
Brennan McCarthy, an attorney for the woman in the harassment case, said Ramos took information she shared with him in confidence "and used it to destroy her life."
Ramos sent a letter to the woman's employer, saying she was a bipolar drunkard, which led to her firing, the attorney said.
"This was malevolence. He had an issue with this woman. I don't know what it was but he did everything he could to destroy her life," "McCarthy said.
Ramos posted veiled threats on social media and also turned his attention to McCarthy.
"This is a man that actually stalked the attorney for the stalking victim," McCarthy said
A Twitter account with Ramos' name and the handle @EricHartleyFrnd is believed to belong to Ramos, a law enforcement source said. It tweeted several times about the paper and Hartley.
By Friday, the account was suspended.
Altomare said his department investigated threatening online comments that Ramos allegedly made against the paper in 2013.
That same year, in a call between a detective and the paper's legal team, the Capital Gazette decided not to pursue charges over fears it would exacerbate the situation, Altomare said.
An Anne Arundel officer wrote that during that call, he indicated that he did not believe Ramos was a threat to the paper's employees.
The officer said the interactions between the suspect and the paper were only on Twitter and civil court filings.
The threatening tweets and rants included "mention of blood in the water, journalist hell, hit man (and) open season," the officer wrote.
Tom Marquardt, the Capital Gazette's former editor and publisher, told CNN on Friday he was disappointed charges were not filed.
"All I saw was a threat against my life and a threat against people who were working for me," Marquardt said. "They felt however, in their professional opinion, that the evidence wasn't there."
Marquardt said the paper's staff at the time got a photo of Ramos with instructions that if anybody who resembled him came through the door, they should call security and 911.
Ramos gave no specific warning he was going to attack the newspaper, authorities said.
In 2014, Ramos was fired from his job as a help desk specialist in the Bureau of Labor Statistics in Washington, according to court documents.
Ramos sued, saying they still owed him money, and wrote in a letter that he was not notified of any misconduct and got no explanation for his firing.
His employer said the federal government demanded he be terminated "citing security suitability concerns resulting from an investigation." The company said it was unaware of the nature of the investigation.
Investigators said they have found evidence at Ramos' Laurel apartment, about a 30-minute drive from Annapolis.
They declined to provide details, other than saying the findings show "what we knew we would find, which is we have one bad guy."