The man named as the Oregon college gunman was an English-born mass shootings fanatic who used to sit alone in the dark.
Chris Harper-Mercer, 26, killed at 10 people at Umpqua Community College in the US state of Oregon, before being fatally shot in a stand-off with police.
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His blog documents an interest in mass shootings, including a recent post about the gunman who killed two US journalists live on air in August. His social media profiles featured content supporting the IRA.
He describes killer Vester Flanagan 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 blog post discussing the recent shooting of a Houston police officer said he did not "agree with the black lives matter protests".
The first entry from July, titled The Material World Is A Lie, reads: "Most people will spend hours standing in front of stores just to buy a new iPhone ... I used to be like that, always concerned about what clothes I had, rather than whether or not I was happy. But not anymore."
He also has a Myspace page which features a photo of him with a gun and pictures of soldiers.
He was the son of Laurel Margaret Harper and Ian Bernard Mercer, who split before he was born, according to reports.
He is said to have moved to America from the UK as a child.
Harper-Mercer lived with his African-American mother, a nurse, at an apartment, according to the LA Times. A neighbour said Harper would often call her son "baby" despite the fact he was an adult.
They also said that Harper-Mercer, who would often wear camouflage trousers tucked into black boots, seemed to carry around a black case with a gun inside and loved target shooting.
The gunman's father, Ian Mercer, said he was "just as shocked as everybody" at his son's actions.
Speaking with a distinctive English accent from his home in the US, he told reporters: "I've just been talking to the police and the FBI and all the details I have right now is what you guys (reporters) have already.
"I can't answer any questions right now, I don't want to answer any questions right now.
"It's been a devastating day, devastating for me and my family.
"Shocked is all I can say."
Bronte Hart, a neighbour in Harper-Mercer's community of Winchester, said he would "sit by himself in the dark in the balcony with this little light".
She said a woman she believed to be the gunman's mother also lived upstairs and was "crying her eyes out" on Thursday.
