Thank you LooseChippings!
By this time, one thing I can conclude is that the player can forge others' e-mail headers very easily. (Is there anyone can explain how come that guy do this? Does he need a program? What's the program like?)
But I am still not sure if the guy can really send e-mails from my outbox. I doubt on it and want to testify it. Can anyone help me on this?
By now, I only got failure despatch report from others (they were suspicious mails from address like
Postmaster@theaa.com,
postmaster@centrica.com,
zybc@peoplemail.com.cn and
null_user_9753@people.com.cn)
and I haven't got any auto failure despatch report from my mail provider as normally.
Looking forward to hearing from this more.
Thanks in advance!
Susan