You can use
pgrep -a find
it will give you a full command line as well as the process ID:
10838 find / -iname png
10839 find / -iname jpg
then you can decide if it's the one you want to kill or not:
will kill the png one.
you can also use
pkill like this:
pkill -x "find / -iname png"
-x means: Only match processes whose names.
Find child process:
use tree to find your desired process, let's say your script name is "script.sh" you can use
pgrep -f script to find it, then pass the output to
pstree to get a list of it's child and kill the find process which is the child of your script.
$ pstree -p $(pgrep -f script)
$ kill 10916