How to stop a linux process

[Glen]

When I used the following line to play a midi file in linux,

return_value = os.system('timidity test.mid')

I have encountered two problems.
1. The python script halts until timidity has finished.
2. If I had control of the script, I can't think how I would stop timidity.

Any advice on the 'area' of python I should be looking at would be greatly
appreciated.

Thanks.