Terminate a chain of processes containing a case in the middle

I have:

Process_A contains a call Activity running Case_B.
Case_B contains two process task running Process_C and Process_D.

Now i use Process_A as starting point (I’m not able to run a case from the cookpit)
In Process_C I use an end signal event. The signal is catch by Process_A that terminate its execution as well.
In reality Process_C terminate, Process_A terminate but Process_D starts because it seams it is not related to the parent Process_A having the Case_B in the middle.
How can i terminate all the instances together using this configuration of process chain ?
Is it possible to start a case without a process wrapping it ? Is it possible to terminate a case catching a signal thrown by a sub process ?