Dear …
RE: Employment Termination
With reference to our previous discussions on __(date and date)__ regarding __(briefly describe the situation at hand)__, __(we/I) now believe you have been adequately notified and warned about your __(unacceptable/poor)__ __(behavior/performance)__. On __(date)__, you were warned that if this problem continued, it would be means for your immediate dismissal.
Since that date, __(I/we)__ have observed that there has not been a noted improvement in your __(behavior/performance)__, and therefore __(I/we)__ __(am/are)__ left with no other alternative but to terminate your employment with __(name of company)__ effective immediately.
As of __(time and date)__, your services are no longer required at __(name of company)__. Enclosed you will find all the appropriate documentation for your employment termination, including your final pay check that represents payment in full for __(#days/weeks/etc.)__.
__(I/We)__ wish you luck with your future endeavors.
Yours truly,