Hillary Clinton is currently under investigation by the FBI: The agency that is overseen by Attorney General Loretta Lynch at the Justice Department. Therefore, it is not appropriate for Bill Clinton to have a private meeting with Lynch while Hillary's investigation is still ongoing. This raises suspicions about how impartial and nonpartisan Lynch can be with the investigation. In short, Bill Clinton's meeting with Loretta Lynch crosses the line.
Bill Clinton should have known better than to go and step onto Loretta Lynch's plane. The Attorney General is doing an investigation into Hillary (Bill's wife) for her use of a private e-mail server. Bill was the Attorney General for Arkansas and should have know that it would look very fishy if he was talking to Loretta Lynch.
Bill Clinton crossed the line by privately meeting with Attorney General Loretta Lynch. Although the conversation may have been innocuous, it gives the appearance of impropriety in light of the ongoing investigation into Hillary Clinton's e-mails. Bill Clinton, a lawyer, should know better. A quick hello could have been conveyed, and there would have been no questions raised.
Bill Clinton crossed the line by privately meeting with the Attorney General Loretta Lynch. Considering that investigations about the Benghazi scandal and Hillary Clinton's use of a private email server and private emails, while in office as the US Secretary of state is underway. Loretta Lynch is the concerned authority, who would be investigating the matter and giving the final verdict, hence Bill Clinton's private meeting with her is highly questionable.
underway to be investigated