First lady Angelica Rivera has returned the $7 million mansion she bought from a firm that won lucrative contracts with the administration of President Enrique Pena Nieto, Mexico's Public Administration Department said Friday.

The department's head also said that neither the president nor his wife had incurred in any conflicts of interest.

But the investigation headed by Virgilio Andrade apparently consisted largely of asking government employees whether they had steered contracts to the firm, and critics have questioned Andrade's independence because he was appointed by the president himself.

After a scandal erupted in 2014 amid news reports about the property, Rivera said in November that she was buying the house from the company on monthly payments with money she earned as an actress.

Returned: A worker stands outside a mansion that belonged to Mexico's first lady Angelica Rivera, located in a luxury neighborhood of Mexico City in the photo above

The company was to hold title to the mansion until it was paid off.

Rivera said she would sell her rights to the property after questions arose about the president's relationship with contractor Grupo Higa.

The mansion was built by one of contractor's subsidiaries.

Just days before the news reports surfaced, Pena Nieto's government canceled a high-speed rail contract that had been granted to the sole bidder, a consortium that included Constructora Teya, another Grupo Higa company.

Lucrative: First lady Angelica Rivera (above) has returned the $7 million mansion she bought from a firm that won lucrative contracts with her husband's administration

Competitors complained the bidding process had been rushed.

Andrade said Friday that Rivera had reached an agreement with the Grupo Higa subsidiary to pay about $635,000 (10.5 million pesos) in rent for the nearly three years she used the property.

The company agreed to return about $875,000 (14.5 million pesos) she had made in payments on the mansion.

Andrade said the investigation showed that Rivera had bought the house before Pena Nieto took office in December 2012, and that there was no evidence that Pena Nieto intervened to steer contracts to the company.

'The investigation shows that my wife's conduct as well as mine were clearly according to the law,' Pena Nieto said later Friday.

The president did, however, recognize that Mexicans had lost confidence in the government that will not be won back with speeches.

Pena Nieto offered 'a sincere apology' to Mexicans upset by what he called 'interpretations' of the irregularities.

Doubts have surrounded Andrade's investigation, in part because of his lack of independence; Pena Nieto appointed him in February to investigate his own administration.

Scandal: In 2014, a scandal erupted amid news reports about the property. Rivera said in November that she was buying the house (above) from the company on monthly payments with money she earned as an actress

Andrade's investigation apparently consisted largely of asking Pena Nieto's office if he intervened in awarding contracts, and asking 111 government employees if anyone had pressured them into awarding contracts.

He refused to answer reporters' questions about whether he had checked the employees' email accounts.

At a three-hour news conference, Andrade refused to answer questions about why Grupo Higa's rail contract was cancelled just days before the mansion scandal broke.

While the government initially offered to have a panel of independent experts review the investigation, Andrade said he had decided not to convene such a panel but instead to post the documents on a government website.

'The important thing is that there is full access for everybody,' he said.

Relationship: Rivera said she would sell her rights to the property after questions arose about the president's relationship with contractor Grupo Higa. The mansion was built by one of contractor's subsidiaries