The mother of a gunman who killed nine people and himself at an Oregon community college allowed her troubled son to have guns.
She also acknowledged in online posts that he struggled with autism, but did not seem to know he was potentially violent.
The online writings by Laurel Harper date from a year to nine years ago and offer fresh insight into Christopher Harper-Mercer, 26, and his relationship with his mother.
Ms Harper and her son shared an apartment outside Roseburg and investigators have recovered 14 firearms - six found at Umpqua Community College, where the killings occurred, and eight at the apartment.
Neighbours of the mother and son in California, where they lived before moving to Oregon in 2013, have said Harper-Mercer and his mother would go target shooting together.
Investigators say Ms Harper has told them her son was struggling with some mental health issues.
In her online postings, Ms Harper talked about her love of guns and her son's emotional troubles but there are no hints of worry that he could become violent.
"I keep two full mags in my Glock case. And the ARs & AKs all have loaded mags. No one will be 'dropping' by my house uninvited without acknowledgement," a three-year-old posting says.
She was referring to a Glock handgun and to military-style rifles. A Glock and a military-style rifle were among the weapons seized after the Roseburg shooting rampage.
Ms Harper wrote in another posting: "I love the long guns & I have an AK-47 en route."
She also complained about gun-control efforts in "lame states".
She posted several times that her son had Asperger's syndrome, an autism spectrum disorder.
One posting reads: "He's no babbling idiot nor is his life worthless. He's very intelligent and is working on a career in film-making."
She wrote that she read aloud to her unborn son from Donald Trump's The Art of The Deal.
Investigators have not yet said whether they suspect a motive in last Thursday's shooting, where Harper-Mercer killed eight students and a teacher before killing himself.
Carmen Nesnick, Harper-Mercer's stepsister, has said he was born in the UK and travelled to the United States as a young boy.
While living in California, Harper-Mercer graduated from a learning centre for students with learning disabilities and emotional problems. His parents divorced when he was a teenager and he lived with his mother.
Harper-Mercer's father, Ian Mercer, who still lives in California, said over the weekend that he said he had no idea his son had any guns.
"How on earth could he compile 13 guns? How could that happen?" Ian Mercer told CNN.
A knock on Ms Harper's door went unanswered during attempts to contact her and her phone's voicemail box was full.
However, the postings included an email address that is linked to Ms Harper.