By DARREN BARBEE A Fort Worth SEC enforcement attorney who exchanged blistering e-mails with Dallas Mavericks owner Mark Cuban is under investigation by the agency’s inspector general despite already being disciplined, according to The Wall Street Journal.The commission has not disclosed what discipline the attorney, Jeffrey Norris, received. A message on Norris’ work phone says he is temporarily on leave."Personnel rules only permit me to say that appropriate action was taken," said SEC spokesman John Nester.Cuban and his attorney did not immediately respond to requests for comment.In its semi-annual report to Congress, the inspector general for the Securities and Exchange Commission said that the office had opened an investigation into a complaint received from counsel for a defendant in an SEC enforcement action, alleging numerous instances of misconduct by several enforcement staff members.At the time it received the complaint, the report says, the inspector general’s office was already looking into a related inquiry involving the "sending of inappropriate e-mails by an enforcement attorney."The report does not name Cuban or Norris by name, but the Journal, citing an unnamed source, confirmed that the matter involves Cuban.In 2007, Cuban and Norris exchanged highly personal and politically charged e-mails when SEC regulators were investigating Cuban over suspicions of insider trading.