Lost email

I have a user who lost many of his inbox email and some of the folders he
had made under inbox. He Knows that he deleted one of the emails in his
inbox then left the room. When he came back noticed some of his folders
missing with the emails that he put in them and most of the emails he had in
his inbox was gone too. He had about 800 or 900 emails in his inbox as he
never has time move them or delete them. He was left with 17 emails in his
inbox.

A coworkers of mine found some a lot of emails in his recycle bin so he did
a restore all but none of the emails or folders came back. Does anyone know
where we can look for the lost email?