His parents were Christians so I doubt they'd have been pushing Al Qaeda stuff his way. Plus I think we'd know by now if that was a possibility. Any radicalisation likely happened via social media, the internet, etc. If he's been searching for stuff and downloading it on his computer then it's likely a solo mission. And we don't know yet if those manuals he downloaded were necessarily the inspiration for the murders. We know he downloaded them and we know he committed the murders but whether the two things are linked is... not yet known? Unless I've not read something.Everybody is looking for an answer, a reason. His parents were immigrants, and history has shown that children tend to follow their family culture. And before I am jumped on, I am not saying they are to blame, it just offers an explanation as to the environment that some, but not all immigrants are raised in can lead to radicalism as they feel they are not part of Western Society.