How to kill a process if it contains a specific word without case-sensitive

Question

IntPtr hwd = FindWindow(null, "Calculator");
if (hwd.ToString() != "0")
SendMessage(hwd, 0x0010, 0, 0);

I'm using this code. It works only when the title matches perfectly. I want to end the process if there is a specific word without case-sensitive.

If the word calculator has the word cula