Michael Tschögl

If you are looking tool for forensic purpose, please have a look below tools that can meet your requirement that supports the EML format as well.

If you are a forensics analyst then for you we have a product called SysTools MailXaminer which specializes in email forensics, It support multiple email formats, More Than 30 Email Formats and many web based email clients, you will surely love to have it in your toolbox:
http://www.mailxaminer.com/supported-email-systems.html

It has a lot of features, Powerful search, Regular Expression, Fuzzy, Stem searches, Proximity , Keyword Analysis:
http://www.mailxaminer.com/features.html

1. Support 30+ email client formats.
2. Support web mail formats such as Gmail, Office 365, Hotmail, Yahoo and Google Apps.
3. Support E01/DD image format.
4. Powerful search techniques such as regular expression, fuzzy, stemming, proximity etc-etc.
5. Tagging and Bookmarks are supported.
6. Review based on shared drive or cloud based.
7. Export to multiple format including Concordance, PDF, EML, PST, MSG, HTML
8. Audit/Trail for action within the tool
9. Skin tone analysis

Please have a demo session, if you can spend around an hour:
http://www.mailxaminer.com/download.html