[stylin19a]

looks like the letter was issued

http://www.freerepublic.com/focus/chat/3795315/posts?page=634#634

[rolling_stone]

minority witness rules: ...As is the case with other witnesses, a minority witness may decline an invitation to testify. The committee can elect to issue a subpoena for testimony under the normal procedures of the House and the committee but is not required to do so

.... https://www.everycrsreport.com/files/20150814_RS22637_dfa69aa94d491669b93e6b8b91e8b46d641d3b4c.pdf