Victimology is not victim blaming. It comes without judgment. But it is necessary to know what avenues to explore.
For example, if I go shopping and someone is looking for me, they would check the shoe store. Clothing store. Kitchen store. But the places they would likely not check would be the electronics store. The tuxedo shop. It's not a judgment about a person. It's knowing the things that are possible for that person, to be able to better investigate.
Plenty of people drink or do drugs. It remains to be seen if that was a factor here. But, it's a possibility in his life, so it's ok to explore that option. Logical evidence (appearing intoxicated, walking the streets instead of going to hotel, getting money and checking balances at ATM in late late night hours) says its a likely factor, so needs to be explored. It's uncomfortable, but it is not a judgment about him. It's just part of victimology- knowing your victim's habits and tendencies. Even if this was say an accidental overdose- someone supplied the drugs and someone rolled him. At least 1 other person knows what happened and it needs to be investigated.