Gerald Walpin, the inspector general who was at the center of controversy in 2009 when he was fired by the White House amid an investigation of an Obama friend, died today. He was 84.

Walpin's son-in-law, Allan Tananbaum, said Walpin was struck by a car while crossing a street in Manhattan.

Walpin was fired in June 2009 for his investigation of the misuse of money in AmeriCorps, the service organization that was part of the Corporation for National and Community Service, where Walpin served as inspector general. The investigation focused on Kevin Johnson, the former NBA star who became mayor of Sacramento, Calif., and was a prominent Obama supporter.

Johnson founded a school called St. Hope, which received about $850,000 in AmeriCorps grants.Walpin discovered that Johnson and St. Hope had failed to use the federal dollars they received for the purposes specified in the grant and had also, as Walpin told me in an interview at the time, used federally funded AmeriCorps staff for, among other things, "driving [Johnson] to personal appointments, washing his car and running personal errands."

Walpin recommended that Johnson and St. Hope be barred from receiving future federal funds.

It turned out to be an enormously controversial recommendation. As Walpin finished his probe, Johnson was elected mayor of Sacramento. If Johnson had been barred from receiving federal grant money, the city might not have been able to receive a share of the billions of dollars in federal stimulus money being handed out by the Obama administration.

There was enormous pressure on Walpin to back off. He didn't. On June 10, Walpin received a call from a White House lawyer. "He said, 'Mr. Walpin, the president wants me to tell you that he really appreciates your service, but it's time to move on,'" Walpin recalled to me later. "[He] said, 'You can either resign, or I'll tell you that we'll have to terminate you.'"

Walpin declined to resign and was fired on the spot. His firing was a violation of rules regarding the dismissal of inspectors general.

Charles Grassley, the Iowa Republican senator who has long been a champion of inspectors general, took up Walpin's case and demanded information from the White House. Not much cooperation was forthcoming. Although some Democrats agreed that Walpin had been wrongfully fired, the White House defended its decision and claimed Walpin, who was then 78, was too "confused" to handle his duties.

He never seemed confused to me. I reported at length on the Walpin case, and spoke to him many times. Walpin was an extraordinarily determined man, and he placed enormous value on integrity in government. If he found wrongdoing, he was going to pursue it until it was made right. That became a problem when the wrongdoer was a White House friend.

Gerald Walpin was born in 1931 in New York City. He graduated from City College of New York in 1952 and in 1955 received a law degree from Yale.

He clerked for two federal judges, served in the Air Force from 1957-60, served in the U.S. Attorney's Office for the Southern District of New York (where he prosecuted, among others, Roy Cohn) and for more than 40 years was a partner at Rosenman & Colin, later Katten Muchin Rosenman.

Walpin leaves behind a wife, Sheila — next April would have been their 60th wedding anniversary — three children, and six grandchildren.