Attachments in

I am trying to extract an attachment from an email using:

tell application “Mail”
set _messages to (selection)
repeat with _message in _messages
tell _message
set _source to source
tell _source
set _text to text of _source
set _attachments to every attachment in _text
return _attachments
(* In the final version, this return statement would be a loop to extract and delete it but it won’t even return the list of attachments
end tell
end tell
end repeat
end tell

However I can’t seem to get it to work. As far as I can tell, the object model is followed. Any ideas what’s wrong?