(CNN) The apparent online writings of the mother of the man who killed nine people at a community college in Oregon discuss guns and the autism spectrum, painting a partial picture of the environment the family lived in, their beliefs and the challenges they faced.

Online posts linked to Laurel Harper, mother of the gunman, are limited and incomplete, but they seem to indicate two things: that her son, Chris Harper-Mercer, had a developmental disorder, and that the family had a familiarity with firearms and gun laws.

On Tuesday, a spokesman for the agencies looking into last week's fatal shooting told CNN that investigators are aware of Harper's alleged social media postings and her son's online writings. Sgt. Jeff Eichenbusch of Roseburg police said that Harper is part of the investigation, just as would be any person who was close to the gunman.

Laurel Harper's apparent online writings come in the form of posts to several websites, usually about health topics. The bulk of the postings were on forums such as Yahoo! Answers and comments on NurseTogether.

Photos: Shooting at Oregon community college Photos: Shooting at Oregon community college Community members attend a candlelight vigil at Stewart Park for those killed during a shooting at Umpqua Community College in Roseburg, Oregon, on Thursday, October 1. The massacre left nine people dead and nine wounded. The gunman also died. Hide Caption 1 of 15 Photos: Shooting at Oregon community college In response to the shooting on October 1, President Barack Obama delivers the 15th statement of his presidency addressing gun violence. "Somehow this has become routine," he said. "The reporting is routine. My response here at this podium ends up being routine, the conversation in the aftermath of it. We've become numb to this." Hide Caption 2 of 15 Photos: Shooting at Oregon community college Students and faculty are reunited with friends and family at the county fairgrounds on October 1. Hide Caption 3 of 15 Photos: Shooting at Oregon community college People wait for information at the fairgrounds on October 1. Hide Caption 4 of 15 Photos: Shooting at Oregon community college Hannah Miles, center, is reunited with her sister Hailey and father, Gary, on October 1. Hide Caption 5 of 15 Photos: Shooting at Oregon community college A student waits to walk off a school bus at the fairgrounds on October 1. Hide Caption 6 of 15 Photos: Shooting at Oregon community college Friends and family are reunited on October 1. Hide Caption 7 of 15 Photos: Shooting at Oregon community college A woman is comforted after the deadly shooting at Umpqua Community College in Roseburg, Oregon, on October 1. Douglas County Sheriff John Hanlin announced at a news conference that the shooter was dead. Hide Caption 8 of 15 Photos: Shooting at Oregon community college Authorities secure the campus after the shooting on October 1. Hide Caption 9 of 15 Photos: Shooting at Oregon community college Students, staff and faculty leave the school on October 1. Hide Caption 10 of 15 Photos: Shooting at Oregon community college A bullet casing is marked at the scene of the shooting on October 1. Hide Caption 11 of 15 Photos: Shooting at Oregon community college People gather at a roadblock near the entrance to the college on October 1. Hide Caption 12 of 15 Photos: Shooting at Oregon community college Authorities respond after reports of the shooting on October 1. Hide Caption 13 of 15 Photos: Shooting at Oregon community college Police search students outside the school on October 1. Hide Caption 14 of 15 Photos: Shooting at Oregon community college A patient is wheeled into the emergency room at Mercy Medical Center in Roseburg on October 1. Hide Caption 15 of 15

Public records link Harper to the same email address used in these posts from a Yahoo! user calling herself "Tweety Bird."

The postings, first reported by The New York Times, make references to Harper having a son who has a disorder on the autism spectrum and of the family having strong pro-gun views.

In response to a question posted on Yahoo! Answers three years ago, the account linked to Harper complains about "lame states" that consider a loaded magazine inside the home the same as having a loaded gun.

"I keep all my mags full. 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 (acknowledgment)," the user Tweety Bird wrote.

In another post, answering a hypothetical question of how gunmen might be charged and sentenced, Tweety Bird argues which gun laws would apply, citing "my son, who has much knowledge in this field."

That post was from six years ago.

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Her apparent views on guns differ largely from her former husband, Ian Mercer, who told CNN the shooting would not have happened if his son, 26, had not had access to 14 guns. All the guns were legally obtained by the shooter or family members over the last three years through a federally licensed firearms dealer, a federal official said last week.

Mercer said he has never held a gun. He doesn't want to, he told CNN. He laid out his personal philosophy on the issue: "I'm a great believer (in) you don't buy guns, don't buy guns, you don't buy guns."

Other nations don't see mass shootings at the same rate the United States does, Mercer said, asserting, "Somebody has to ask the question: How is it so easy to get all these guns?"

Mercer and Harper were married in 1989 and separated after 11 months, according to California court documents. They divorced in 2006 and had joint custody of their son.

Ian Mercer said his son had lived with his mother. They moved to Oregon about two years ago.

Advice on medical issues

The majority of the online posts linked to Harper, however, are not about guns or politics or law. She describes herself as a nurse, and mostly offers advice or expertise on health issues.

State records show that Laurel Harper is a licensed practical nurse in Oregon.

When strangers ask about a sore arm after getting multiple vaccines or taking vital signs or how to fill out nursing forms, Tweety Bird is generous with her responses.

Tweety Bird often shares her email address -- the one public records link to Harper -- in these posts, encouraging those with questions to reach out to her directly for additional guidance.

One area she claims expertise in is autism.

In several posts, she makes references to having Asperger syndrome, considered to be on the high-functioning end of the autism spectrum. She also makes references to her son having the same developmental disorder.

While dispensing advice on handling anxiety five years ago, Harper purportedly wrote online that "I have Asperger's and I didn't do so bad. Wasn't easy (understatement) but it can be done."

In other online posts, she appears to share that "I also have an Asperger's kid," and that "my son has Asperger's. He's no babbling idiot nor is his life worthless. He's very intelligent and is working on a career in filmmaking. My 18 years worth of experience with and knowledge about Asperger's syndrome is paying off."

The account linked to Harper also makes reference to her son having been "a headbanger" as a kid, as she dispensed advice on how to deal with a child who might injure himself.

Multiple attempts by CNN to reach Harper have been unsuccessful.

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Autism spectrum disorders can cause significant social impairments, communication problems and restricted, repetitive behavior patterns. But studies have shown there is no direct link between Asperger's and violence. The question was also raised three years ago, after Adam Lanza, who was said to have Asperger's, killed 26 children and adults at Sandy Hook Elementary School in Newtown, Connecticut.