Where to put Using block when open Process?

I have process that i am opening and create file on dist and subscribe to this procees ProcessExitedEvent:

public int InvokeProcess(WiresharkProcesses process, string args)
{
    try
    {
        string processToInvoke = null;
        ProcessStartInfo startInfo = new ProcessStartInfo();
        Process pros = new Process();
        startInfo .FileName = processToInvoke;
        startInfo .RedirectStandardOutput = true;
        startInfo .RedirectStandardError = true;
        startInfo .RedirectStandardInput = true;
        startInfo .UseShellExecute = false;
        startInfo .CreateNoWindow = true;
        startInfo .Arguments = args;
        pros.StartInfo = startInfo ;
        pros.ErrorDataReceived += pros_ErrorDataReceived;
        pros.OutputDataReceived += pros_OutputDataReceived;
        pros.Exited += (object sender, EventArgs e) =>
        {
            if (ProcessExitedEvent != null)
                ProcessExitedEvent(pros.Id);
        };
        pros.EnableRaisingEvents = true;
        pros.Start();
        pros.BeginOutputReadLine();
        pros.BeginErrorReadLine();

        return pros.Id;
    }
    catch (Exception)
    {
        return -1;
    }
}

private void ProcessExitedEvent(int processId)
{
   // Copy file
   // Delete file
}

This process create file on disk and after ProcessExitedEvent event fired i want to copy this file to another location and than delete the old file, but although the event fired after the process exit the my code failed to delete the old file because the file is still in use so i want to ensure that my process die by using using block so where i need to put this block ?