BlackRock Inc (BLK.N), the world's largest asset manager, has agreed to buy a Mexican infrastructure investment fund that financed projects for a contractor at the center of a scandal which embroiled President Enrique Pena Nieto.

BlackRock announced its deal to buy Infraestructura Institucional, also known as I Cuadrada, on Friday, but gave no details.

It will pay around 1.1 billion pesos ($71 million) and keep some of the fund's key senior management, said a person familiar with the deal, who declined to be named as the terms were not public.

Two of the six projects listed in Infraestructura Institucional's most recent quarterly filing were built by companies owned by contractor Juan Armando Hinojosa.

Mexico's federal auditor is investigating contracts held by Hinojosa after news of real estate deals he made with political figures sparked national outrage last year. Local media reported that he sold a luxury home in Mexico City to the first lady, and the Wall Street Journal reported that he sold a house to Finance Minister Luis Videgaray at a below-market interest rate.

His companies have won millions of dollars worth of public contracts during Pena Nieto's 2005-2011 governorship of the State of Mexico and his presidency. One of the companies was part of a Chinese-led consortium awarded a multibillion-dollar high-speed train contract last year. That contract was later nixed, days before news of the real estate deal with the first lady.

The two Infraestructura Institucional projects with Hinojosa represent around 16 percent of total assets held in the fund's two investment vehicles, including long-term accounts receivable and investments in joint ventures. When including all committed capital to the fund, it represents 9 percent of the total.

BlackRock's purchase of the fund would make it a partner with Hinojosa in one of the projects, a hospital in the State of Mexico, according to a source.

"BlackRock has had a long-standing presence in Mexico; whether doing business here or anywhere else in the world, we always seek to put the appropriate controls in place," BlackRock Latin America head Armando Senra said on Friday. He declined to answer specific questions about Grupo Higa.

Executives from Infraestructura Institucional did not respond to requests for comment. Grupo Higa, contacted by Reuters, said there was no one available to comment until Monday.

Founded in 2010, Infraestructura Institucional has committed 585 million pesos of convertible debt to the Zumpango Regional Hospital, a first-quarter stock exchange filing shows. It has converted 185 million pesos-worth into shares.

The hospital in the State of Mexico was built by a consortium led by Constructora Teya, part of Hinojosa's Grupo Higa, under a contract won in 2009. Hinojosa still holds a stake in the hospital, one source said.

Infraestructura Institucional also has a 600 million peso credit line with Autopistas de Vanguardia SA de CV, a Grupo Higa subsidiary, which in 2007 won a 30-year concession to build a toll road between Toluca and Naucalpan, also in the State of Mexico.

Infraestructura Institucional runs two "CKDs", special listed investment securities created in 2009 to allow Mexico's pension funds to increase returns and diversify by investing in infrastructure.

The first fund has around 3 billion pesos in committed capital. The second, with 10 billion pesos of capital committed, is larger and currently mostly invested in Mexican government debt.