Maybe some states have to initiate criminal proceedings before killing people, but other states are happy to kill people, including their own citizens, including children, without any criminal proceedings:

https://en.wikipedia.org/wiki/Anwar_al-Awlaki

https://en.wikipedia.org/wiki/Killing_of_Abdulrahman_al-Awla...

(To be fair, most countries have vague laws and corrupt courts so having a court in country X decide that someone should be executed is hardly any better, in practice, than having Barack Obama order the execution.)