The Serbs could just accept the Austrian demand to try those responsible, such as Apis. What could Austria do after they hung Apis, the guy responsible? Which is what the Serbs did after they tried him themselves, in OTL.
It was also serve as a cautionary example to other secret services, the way the assassination of Kennedy caustioned the CIA to stop assassinating foreign heads of state on the grounds that that worked both ways.
It was also serve as a cautionary example to other secret services, the way the assassination of Kennedy caustioned the CIA to stop assassinating foreign heads of state on the grounds that that worked both ways.