The investigation by the FBI into the private email use by Hillary Clinton while she was secretary of state has expanded to look into whether there was a possible intersections of the State Department and Clinton Foundation business which might have violated the laws of public corruption, said an unnamed source with intelligence.

The new track of the investigation is in addition to the FBI’s focus on any classified material that might be found on the personal server of Clinton.

One source indicated, that agents were investigating the possible intersection of donations from the Clinton Foundation, the dispensation of contracts of the State Department and if regular processes had been followed.

The development comes following reports in the press the last year about the potential overlap of Clinton Foundation and State Department work and the questions over whether donors had benefited from contracts inside the administration.

The foundation is a public charity and in 2013, had contributions and grants of more than $144 million.

Sources say that there is pressure within the FBI to pursue this case.

One source in intelligence said that agents with the FBI would upset if no prosecution was pursued since many public corruption cases previously have been made and prosecuted successfully with far less evidence than what has been emerging in the current investigation.

The FBI is on edge following the way in which the case was handled involving David Petraeus the former Director of the CIA.

In the investigation of Clinton, the number of emails that are classified has increased to over 1,300. An appeal in 2015 by the U.S. State Department to challenge the classification of Top Secret of two or more emails failed and that is now considered a closed matter.

On Monday, a number of conservative critics were quick to voice their opinion.

Reince Preibus the Republican National Committee chairman said in a prepared statement that the email server investigation now including a public corruption angle was a development that was troubling.

He added that the favoritism toward Clinton Foundation donors from the State Department was undeniable and that Democrats must be rethinking now whether it was advisable to put everything into one basket.