The deadliest mass killing in the state’s history had taken place a few miles away and to the staff and customers of the Roseburg Gun Shop it was clear they faced a grave threat – from Barack Obama.

Authorities had just discovered a cache of 13 weapons possessed by the shooter, Chris Harper Mercer, but the man they feared was thousands of miles away in the White House, plotting, as they saw it, to confiscate their weapons and leave them defenceless.

“I’ve just ordered some more ARs,” said the owner, Candi Kinney, referring to assault rifles. “There’s always a rush on them after a big shooting. We can’t keep the stuff on the shelves.”

A lifesize cardboard cutout of the president with an Arab keffiyeh scarf stood at the door with a mocking sign: “Gun salesman of the year.”

A sign in the Roseburg Gun Shop. Photograph: Rory Carroll/The Guardian

The fact that this shooting had happened not in Aurora, or Columbine, or Sandy Hook, but up the road at Umpqua community college, leaving 10 dead and shocking this rural Oregon community, seemed all the more reason to stockpile and carry guns.

“They need to leave us our guns and go after the lunatics,” said Ray Lee, 61, a retired diesel mechanic cruising the aisles of rifles and handguns.

Tanner Langdon, 39, shopping for a holster for the 9mm wedged in his jeans, said the massacre would have been averted if the victims had been armed. “A whole different outcome.” He patted his gun. “I refuse to be a victim.”

While gun control advocates hope the president’s blistering response to Roseburg’s tragedy will prompt reform, Roseburg hopes it will produce more armed citizens.

Interviews with almost a dozen residents on Friday yielded unanimity – even in the queue of people lining up to donate blood at a tent set up downtown. “Obama sucks, he’s stupid,” said Chris Allen, 43, a mill worker. “If criminals want to get guns they’ll get guns.” Allen had lost a brother to gun violence – a separate tragedy which only steeled his pro-gun resolve.

“Make this a gun-free zone and you paint a target on us,” said one elderly man, a laptop shopper at Staples who declined to give his name. “Criminals will come here because they’ll know no one will damn well shoot back at them.”

The fact Mercer had legally acquired an arsenal – he passed background checks – and had no criminal record before murdering nine people and wounding 10 more dented residents’ passion for gun rights not a bit. It was an armed police officer, after all, who cornered and fatally shot Mercer, ending his rampage.

Oregon allows permit-holders to carry concealed weapons but Umpqua college did not, leaving staff and students vulnerable – and now Obama wanted to do the same to all Americans, said Del Appelgarth, who works at the Roseburg Gun Shop. “He wants to control everything, leave us defenceless. What he said was a slap in the face.”

The defiant commitment to gun rights after Roseburg contrasted with other massacres in Aurora, Tucson and Santa Barbara, which immediately produced grieving victims demanding greater gun control.

Douglas county sheriff John Hanlin set the tone by standing by a 2013 letter to vice-president Joe Biden saying stricter firearm regulations would be an “indisputable insult to the American people”.

Jason Gray, an anaestheologist at Mercy Medical Center, which received 10 wounded, said the main difference between road accident trauma and gunshot trauma was that gunshots penetrated.

Many of the wounded suffered multiple wounds, he said. One died in the emergency room. “Call it luck or the grace of God but millimetres can make the difference between walking out of here, or not.”

The profile of Mercer that emerged was of a troubled loner. The 26-year-old lived with his mother in an apartment a few miles from the college.

In a blogpost appearing to be by Mercer, the author described Vester Flanagan - who killed two US journalists live on air in August - as a man who “wanted the world to see his actions” before adding: “Seems the more people you kill, the more you’re in the limelight.”

A neighbour, Bronte Hart, said he lived upstairs and would “sit by himself in the dark in the balcony with this little light”.

Mercer’s stepsister, Carmen Nesnick, expressed shock and confusion over her stepbrother’s role in the attack, telling reporters he was a “nice guy”.

“All he ever did was put everyone before himself,” said Nesnick, who lives in California, where Mercer lived before moving to Oregon. “He wanted everyone to be happy.”

In the aftermath of the rampage, harrowing details emerged of the scene inside the classroom. Witnesses said the gunman demanded to know students’ religion before shooting them.

Hannah Miles, a 19-year-old freshman who had been in her writing class when her teacher got a call from security saying the school was in lockdown, said she heard gunshots from a neighbouring classroom.

“There was a huge pop. It sounded like a ruler smacking against a chalkboard. Everyone jumped and we didn’t know what was going on. Then there was another one,” Miles told reporters. She was eventually evacuated by police from the locked classroom.

Seven weapons were recovered at Mercer’s home, in addition to the six weapons that were recovered on the campus, Celinez Nunez, of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), told reporters during a Friday morning press briefing. A bulletproof jacket and five extra magazines were also recovered at the scene.

All 13 weapons were purchased legally by the shooter or a family member in the last three years, Nunez said, as a national debate reignited over long languishing gun control reforms. The Douglas County Sheriff’s department said on Twitter that investigators recovered five pistols and one rifle from the crime scene.

Sheriff Hanlin said during the press conference that officials were still working to notify victims next-of-kin and said the medical examiner’s office was expected to release their names and brief biographies Friday afternoon.

Hanlin has refused to name the gunman out of deference to the victims and their families, and chastised the media for reporting his name, saying it “glorified” a murderer.