From Bloomberg News: 

The National Basketball Players Association, already in turmoil after President Derek Fisher asked for independent reviews of its finances and business practices, is being investigated by the U.S. Attorney’s Office in Manhattan, the union said in a statement.

Union Executive Director Billy Hunter was notified of the investigation by subpoena for documents on April 25, according to two people with direct knowledge of the situation. The people were granted anonymity because they weren’t authorized to discuss the investigation.

“The NBPA will cooperate fully with the government’s investigation,” the union statement said.

via NBA Players Union Under Investigation by U.S. Attorney’s Office - Bloomberg.

This week Yahoo Sports reported on a series of allegedly disreputable dealings by Hunter during his tenure as executive director including a multi-million dollar investment into a banking firm which his son held a board position on.  and Bloomberg previously reported that the NBPA had paid members of Hunter's family over $4.8 million.  

Hunter has denied any and all wrongdoing in the press. 

Last week the NBPA's executive committee unanimously voted in no-confidence of union president Derek Fisher and asked for his resignation effective immediately, a request which Fisher has denied. Fisher had previously sought an independent audit of the NBPA's finances over the last several years, a request which appears more and more advisable as evidence of Hunter's decisions mount.  

The plot thickens for a union already in chaos.