What is the emerging “disturbing picture” the article refers to? He was a good student, smiled a lot, was allegedly a registered Republican, and - in one photo - is seen wearing a patriotic t-shirt. He made a small contribution to a leftist group, and that’s about it.
The disturbing image unrevealed is how he decided to crawl up on a roof and take a shot at POTUS Trump. My guess is that a series of deceitful, maniacal, derange-riddled emails he received from dozens of political action committees resulting from his giving his email address to ActBlue set him off. But it’s just a guess.