Citing sources familiar with the matter, the Washington Post reported Friday that New Jersey Democrat Sen. Bob Menendez is under investigation by a federal grand jury in Miami over his dealings with donor Salomon Melgen.

The grand jury is investigating whether Menendez intervened improperly on Melgen’s behalf regarding a port-security contract with the Dominican government, the Post reported.

J. Scott Applewhite / AP file photo

Sen. Bob Menendez, D-N.J., is being investigated by a Miami federal grand jury for his role in advocating for the business interests of a wealthy donor and friend, The Washington Post reported Thursday, March 14.

Menendez acknowledged earlier this year that he failed to disclose flights to the Dominican Republic  paid for by Melgen, a Florida ophthalmologist.  

In a statement, a spokesman said Menendez has acted properly.

“Every day, more evidence emerges that the false smears against Senator Menendez are nothing but an elaborate campaign orchestrated by Republican political operatives,” said spokesman Paul Brubaker. “As we have said all along, we welcome any review because Senator Menendez's actions have always been appropriate, and we believe the facts will confirm that.”

Conservative web site The Daily Caller has reported allegations that Menendez, the chair of the Senate Foreign Relations Committee, also patronized prostitutes while in the Dominican Republic.

But reports indicate that FBI agents have found no evidence supporting those charges.

Menendez vigorously denies those prostitution claims.

This story was originally published on Fri Mar 15, 2013 10:51 AM EDT

SANTO DOMINGO, Dominican Republic - A Dominican woman who previously stated in a video that she was paid to have sex with Senator Robert Menendez of New Jersey now says the allegations were false, according to a sworn statement released by a lawyer on Monday.

The notarized affidavit was distributed by a prominent Dominican lawyer and friend of Menendez, Vinicio Castillo, who said it had been handed over to prosecutors. Castillo is not acting as the lawyer to the woman.

In her sworn statement, Nexis de los Santos Santana denied ever meeting Menendez and said she never agreed to be filmed.

Menendez, a Cuban-American Democrat who chairs the Senate Foreign Relations Committee, won re-election to a second term last year. He has repeatedly denied the sex claims, calling them "politically motivated" smears.

Asked on Monday night about the affidavit, a spokeswoman for the senator declined to comment. The affidavit was first reported by the Washington Post.

The original videotaped interview with the woman features her saying that Menendez paid her for sex and that she was cheated out of the full amount he had agreed to pay.

But according to the affidavit released on Monday, the woman now says she was paid to read from a prepared text and was videotaped without her consent.

Related:

After ethics complaint, Sen. Menendez pays $58,500 for two flights to Dominican Republic