Try to kill a spawn process with shell true and detached true nodejs

I am trying to write a simple node.js application in order to run selenium in a dedicate shell and then close the shell and the corresponding child process (at the moment after a timeout of 5 seconds in order to test it). Here the code I have so far:

const spawn = require('child_process').spawn;
const seleniumHub = spawn('java', ['-jar', 'selenium-server-standalone-2.48.2.jar'], { shell: true , detached: true });

seleniumHub.stdout.on('data', (data) => {
    console.log(`stdout: ${data}`);
});

seleniumHub.stderr.on('data', (data) => {
    console.log(`stderr: ${data}`);
});

seleniumHub.on('close', (code) => {
    console.log(`child process exited with code ${code}`);
});

setTimeout(function () {
    // process.kill(seleniumHub.pid); error - it cannot find the pid
    // seleniumHub.kill('SIGINT'); completely ignored 
}, 5000);

Selenium correctly runs, but I am not able to close the opened shell. If I try to close it through its pid, I get an error that the pid doesn't exist. If I try to call the kill method on the child process, it completely ignores the command.Any suggestion please?

Thanks

p.s. I am on a Windows machine

via quirimmo