In answer to your question, this person is both a victim and cold blooded killer. You mention that this person was bullied, ergo, he is a victim. On the other hand though, the question we really need to address is WHY murder others who may or may not have had anything to do with his pedicament. There are conflicting reports about whether he was bullied, so I'm sure it will all come to light during the investigation.
At the same time, where is the intervention that is so needed for bullied students? Did parents, other family members, friends, online "friends" or teachers have any idea about this person's state of mind? Where did he obtain the weapon? There are more questions than answers to this terribly sad incident.