TCL question

I building a script that will filter messages based up the user in EVN.5  .  I want to delete all messages where the user ends with “$$XYZ”.  So basically, it boils down to creating a regular expression to will recognize that.  So, in the tcl environment, I created a user of ABC$$XYZ.  And I’ve tried several regexp commands with parameters such as:

regexp “$$XYZ$” $user  , but that gives me a zero value.

Also

regexp  {$$XYZ}$ $user, which gives me an error

Any ideas?