In a letter to Attorney General Jeff Sessions on Tuesday obtained exclusively by Fox News, Rubio said that Americans “deserve to know that U.S. laws are enforced regardless of any individual’s past position.” He encouraged the department to determine whether Kerry violated the Logan Act or the Foreign Agents Registration Act.

Sauce:

http://www.foxnews.com/politics/2018/09/18/rubio-asks-doj-to-determine-if-kerry-violated-federals-laws-meeting-with-iranian-officials.html

Looks like as it becomes a busy time for Sessions.