>Yes you can know. It is not like this was the first bad thing Saudis have done under his command.
Depends on how bad you're talking about.
Saudis are not known as people who kill in other countries. They actually have a robust reputation of kidnapping them and bringing them to KSA (and even of the known kidnapped ones, I think all are still alive). Even within the country, they're known more for making people disappear - temporarily. As in family has no idea where the person is - but usually find out about a year later - and the person is usually in prison - not dead.
Saudi Arabia is known for executing dissenters - but not in a shadowy manner. They arrest, they bring serious charges, and then execute publicly. When they do this often enough, there is not much rationale for them to assassinate people in their own country in a hidden way.
I feel that just because we know of many brutish things the Saudis have done in the past, we are extrapolating to things they likely do not do often. The opposite of the halo effect, if you will. I've seen this often, where people conflate the different Middle Eastern countries and attribute the problems in one country to those in the other - without evidence (e.g. believing honor killings are common in Saudi Arabia).
I don't believe this scenario is at all the norm amongst the Saudi government. I could be wrong, and would be happy to be shown otherwise.