Updated

A Homeland Security Department employee has been placed on leave for wearing a Halloween costume that drew complaints from other workers as racially insensitive — even as it won "most original" honors from managers at an agency party.

An inquiry is under way to determine proper sanctions in the incident, Homeland Security Secretary Michael Chertoff said Tuesday. He declined to criticize Julie Myers, assistant secretary of the Immigration and Customs Enforcement division, who had apologized on Friday.

The unidentified employee's costume of dreadlocks, dark makeup and prison stripes was deemed by Myers and two other managers as the "most original" at the party. After receiving complaints from some employees, Myers e-mailed an apology to her staff, saying a few costumes at the party were inappropriate and offensive.

Myers posed for photos with the employee, but they were discarded, ICE spokeswoman Kelly Nantel said.

"People do dumb things," Chertoff said. "I get very perturbed when there's anything that is done that suggests with respect to enforcement of the law we are anything but evenhanded.

"The idea you can come and impersonate someone of another ethnic group, that is completely unacceptable," Chertoff said.

At the White House, Bush spokeswoman Dana Perino said: "Obviously we do not tolerate inappropriate behavior at the Department of Homeland Security." Once the facts are determined, "we are sure that the department will take all necessary and appropriate actions," she said.

Chertoff said Myers was right to apologize for the costume.

"I'm quite sure it bothers her. She was kind of caught by surprise by this and in the middle of the party and I know she's mortified, but I think she's doing what she needs to do at the moment," Chertoff said.

In addition, Myers contacted members of Congress and an association of black DHS workers about the costume, Chertoff said.

Myers was installed in her post by President Bush while the Senate was in recess after it became clear she might not win Senate confirmation.

Some Democrats have questioned her qualifications for the job and whether she received it because she is the niece of Gen. Richard B. Myers, a former chairman of the Joint Chiefs of Staff. She also is married to John Wood, former chief of staff to Chertoff.

A Homeland Security panel of the Senate allowed her to keep her post in September, saying she had eased concerns about her qualifications.

Myers' agency is responsible for apprehending and jailing violators of immigration and customs laws, including conducting raids at work sites to round up undocumented workers.