Why have the investigators not come forth and tell us what kind of drugs the kid was on, prescribed or illegal? The Columbine massacre shooters were on prescription drugs for depression, which unfortunately, have terrible side effects for some people. Some of the known side effects are a higher risk for suicide. However, I barely recall mention of it in the mass media. Maybe it's because board of directors for big pharma also sit on boards of major media giants and they don't want to see drugs pulled from distribution and major lawsuits against big pharma.
I'm sure the investigators can determine what this guy was looking at online if they have access to his computer(s). They should also be able to determine his medications he had in his body at the time of the shootings. The big question is, Will the news media report on it?
I found one news story which references a black bag which the shooter and his dad were arguing over on the day of the shooting. The shooter had removed the bag from the family car. Someone else found the bag and reported it to the police and the police will not comment on the bag's content. Could be nothing, or could be even more bizarre.