how to kill a subprocess

[cerr]

Hi There,

I'm calling a python script from a php script which again calls a perl
script with subprocess.popen().
This seems to work fine so far only that once the python script
completed it is becoming a zombie because the perl script in the
background is still running... so before i exit the python script, i
would need to kill my perl subprocess.
How can i do so?
Thank you for hints & suggestions!
Ron