Firing of IG followed his probe of Obama friend

White House says the move was "carefully considered."

After criticism from a high-ranking Republican senator over President Obama's dismissal of the inspector general overseeing AmeriCorps Thursday, the White House has provided assurances that the decision was "carefully considered" and conducted in full compliance with the Inspector General Reform Act.

Gerald Walpin, inspector general for the Corporation for National and Community Service, recently spearheaded an investigation into the alleged misuse of AmeriCorps grants by a nonprofit agency run by recently elected Sacramento, Calif., Mayor Kevin Johnson, a former National Basketball Association star and a friend of Obama's.

Walpin's conduct of the investigation has been questioned by the acting U.S. attorney for Sacramento, who referred the case to an ethics panel that oversees IGs.

Obama's announcement Thursday that he intended to fire the AmeriCorps overseer prompted a fiery letter from Sen. Charles Grassley, R-Iowa, a champion of federal watchdogs, who cautioned that Obama's abrupt decision to terminate Walpin could demonstrate a threat to the independence of federal IGs.

In a written response to Grassley sent late Thursday, White House Counsel Gregory Craig attributed Walpin's dismissal to the U.S. attorney's complaint and subsequent request that his conduct of the Sacramento investigation be reviewed by the IG oversight panel.

"We are aware of the circumstances leading to that referral and of Mr. Walpin's conduct throughout his tenure and can assure you that the president's decision was carefully considered," Craig said.

Walpin's investigation of Johnson's St. HOPE nonprofit agency alleged that managers improperly diverted over $800,000 in AmeriCorps funding from 2004-2007. Federal officials subsequently determined that the allegations did not warrant criminal charges, and the mayor attributed any improprieties to "administrative errors."

St. HOPE repaid almost $425,000 in the federal funds as part of a settlement in April.

Danielle Brian, executive director of the Project on Government Oversight, said Johnson's connection to Obama warrants a hard look by lawmakers to assure the legitimacy of Walpin's dismissal.

"I hope Congress holds hearings soon," she said.