Android :: How To Kill Background Applications?

I am currently writing a program to kill processes that the users choose to end. From the log Cat, I notice that a Signal 9 has been sent to the application but the process is still running. I am only able to kill my own process through the code below. I understand that the kernel only allow killing of processes that have some relation to my program, but how do I kill other processes other than my own?
Below is my code: android.os.Process.killProcess(processID);