The father of a Muslim-American soldier killed in Iraq who is caught up in a war of words with Republican presidential candidate Donald Trump is an immigration lawyer who specializes in a highly controversial program accused of letting immigrants buy their way into the U.S.

Khizr M. Khan's website notes that he works to help clients with the E-2 and EB-5 programs that let overseas investors buy into U.S. companies and also provides green cards for family members.

It also said that he helps in the purchase of U.S. real estate and businesses. The website lists his ability to practice in New York, though it gives a Washington phone number for the lawyer who lives in Virginia. A man who answered the phone said the website was correct, though he would not identify himself.

"The E-2 and EB-5 are two of the most notoriously abused visa categories that essentially allow wealthy foreigners to buy their way to U.S. residency, and possibly citizenship, with a relatively modest investment," said Jessica Vaughan, the policy director for the Center for Immigration Studies.

The EB-5 program has been caught up in multiple scandals and critics are pressing Congress to kill it.

"The EB-5 is literally a 'citizenship for sale' program in which a visa for a whole family can be bought for as little $500,000," Vaughan told Secrets. "It is literally a 'citizenship for sale' program, and it's an amazing deal. Compared to other countries, America is the Walmart of investor visa programs," she added.

One criticism is that it allows an immigrant to invest $500,000 in an approved type of business and in return get a set of green cards for the investor, the investor's spouse, and all their under 21-years-of-age children.

Other documented problems include foreigners getting fleeced in fraudulent schemes to help them invest in the U.S.

There is no indication that Khan's clients have been caught up in the controversies

The Center for Immigration Studies has written several reports on problems with the green card investor program.

Khan also offers other immigration services, according to his website:

KM KHAN LAW OFFICE

Khizr Muazzam Khan

Attorney at Law

International Business Legal Advice and Representation

At the KM Khan Law Office we recognize that world economies are rapidly becoming more interdependent and integrated. We advise businesses and business owners from around the globe on a wide range of legal concerns, including:

— How to conduct business in the different parts of the world including the United States, Latin America, Asia, Middle East.

— How to select an appropriate business form - partnership, corporation or joint venture.

— The purchase or sale of commercial real estate.

— Issues related to franchise business.

— Legal representation in litigation and arbitration to resolve business dispute.

— E2 Treaty Investor and EB5 Investor Services and Immigration Services.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com