That's a great question.
There are several international laws that are at play to prohibit most of this behaviour. Aside from this being a breach of sovereignty of the other country the autocrat is reaching into, there are also, depending on the specifics of what happened, international laws against enforced disappearance, against hostage taking and against physical assault in many countries' criminal codes. That's domestic law in addition to international law. It's prohibited to engage in the targeting of civilians. That may be at play in some instances. It would be a very fact-based scenario, but we do have a multitude of laws.
I think the question becomes how those laws are enforced and what's actually done. To give a particular example, in the international framework, we have treaty bodies and mechanisms. Treaty bodies, for example, will monitor states parties' compliance with international treaties. Take enforced disappearance, for example. There's a committee that will monitor states parties' compliance with those provisions. Countries can make reservations, or they can fail to opt in to whatever protocol, depending on how the treaty is structured. It changes a little, but countries can basically not give the committee the right to hear individual communications. When it comes to treaties that have a recourse with the ICJ, states can reserve out of that.
There's a lot of that going on, where dictatorships in particular take advantage of those opt-out procedures and those reservations to make it very difficult to respond to, even when situations are in violation of the law.