President of Mexico Enrique Pena Nieto and first lady Angelica Rivera Hurtado arrive at Brisbane Airport ahead of the G-20 summit in Brisbane, Australia. G20 Australia/Patrick Hamilton/AP

Mexican President Enrique Peña Nieto's family has again come under scrutiny for its property dealings, this time for the first lady's use of a luxury property in Florida owned by a businessman with ties to the first family.

According to a report by The Guardian, Angelica Rivera, the president's wife, has been using two units in Ocean Tower One, a gated community in Key Biscayne.

One of the units was purchased by Rivera in 2005, but the other is owned by Grupo Pierdant, a Mexican firm.

Pierdant has let Rivera use its unit in the building, "in effect allowing them to be managed as a single unit," The Guardian notes, adding that the apartments share the same phone number and that a woman who answered the phone said packages could be sent to either address. "It's the same," the woman said.

In early 2014, Pierdant paid the property tax for its unit as well as for the unit owned by Rivera, which accrued a tax bill of $29,703, according to The Guardian.

Ocean Club Tower One, center, in Key Biscayne, Florida. Google Maps

Ricardo Pierdant, the company's founder who has numerous business dealings in the US and Mexico, quickly hung up when The Guardian called him about the property, but he told Univision that he had lent the apartment to Rivera "several times" and that it was "totally false" that he had paid property taxes for the apartment that she owned.

Peña Nieto's spokesman called The Guardian's report false and said that the suggestion Grupo Pierdant could bid on government contracts was "speculation"

This is not the first appearance of impropriety in the first family's property dealings or in its relationships with current or potential government contractors.

This particular case has reminded many of the "Casa Blanca" scandal of late 2014, which emerged after it was revealed that Rivera was buying a seven-bedroom mansion in an upscale Mexico City neighborhood from Grupo Higa, another large government contractor.

The Casa Blanca, a home in an upscale part of Mexico City. Aristegui Noticias

The first lady returned the property, and an investigation cleared the president of wrongdoing — though many Mexicans scoffed at that finding, as the investigation was led by a friend of the president and the Mexican finance minister.

The links between Peña Nieto and Grupo Higa, which is led by a longtime friend of the president, are extensive. A New York Times report in August last year found that the firm had gotten more than 80 government contracts and received $2.8 billion in state money.

A Reuters investigation last year also suggested that Peña Nieto had misrepresented how he had acquired several properties on tax documents.

"Our elites (political, religious, business, intellectual) simply refuse to understand the concept of conflict of interest," Rodolfo Soriano, a sociologist in Mexico City, tweeted after Peña Nieto was cleared of wrongdoing in August last year.

New lows

The scandals that have developed around Peña Nieto's business and property dealings have undercut his efforts to position himself as a reformer and likely remind many of the deep networks of corruption and influence-peddling that existed when his party, the PRI, ran Mexico as a de facto one-party state for most of the 20th century.

Mexico's President Enrique Pena Nieto sits during a meeting with lawyers in Mexico City Thomson Reuters

The controversies, along with anemic economic growth and growing violence, have damaged Peña Nieto's standing with the public.

His approval ratings have steadily declined for much of the last two years, hitting a record low of 23% in a poll released by Mexican newspaper Reforma this week, down 7 points since April.

It is the lowest approval rating for a Mexican president since the latter half of the 1990s, and 60% of respondents said security in Mexico had worsened, while about 70% said poverty and violence had gone up over the last year.

Reforma's poll also found that 55% of those surveyed thought corruption in the federal government had gotten worse — up from 40% who said the same in April.

Editor's note: The original Guardian report suggested that Pierdant's potential bidding on a Mexican government contract raised the possibility of a conflict of interest. However, on September 16, 2016, The Guardian acknowledged that neither Pierdant nor his companies had gotten any government contracts nor bid on them and took down its report. This post has been edited to reflect that correction.