I think I found the answer. By using Popen with close_fds = True I was able to start up a process that was independent and without handles to the parent.
For docs look here and search for close_fds.
Or, on Windows, if close_fds is true then no handles will be inherited
by the child process. Note that on Windows, you cannot set close_fds
to true and also redirect the standard handles by setting stdin,
stdout or stderr.
Note this solution only works on Windows. I have no idea about any *nix system.