FBI officials would not disclose the name or home office of the missing employee.
As of late Friday, the Treasury Department was still searching for "a few" of the 1,200 employees it had housed in the World Trade Center complex, said Jimmy Gurule, the agency's undersecretary of enforcement. Each of the Treasury agencies with offices in the complex confirmed that all of their employees were accounted for on Monday. Treasury did not respond to inquiries asking if other department employees were still missing.
At least 117 federal workers and 10 contractor employees perished in the joint terrorist attacks on New York and the Pentagon last week. In addition to the 124 civilian, military and contractor employees who are presumed dead at the Pentagon, three federal employees were on board United Airlines Flight 93 that crashed about 80 miles outside Pittsburgh.
The crash claimed Fish and Wildlife Service manager Richard Guadagno, 38, and two Census Bureau employees, Marion Britton, 53, and Waleska Martinez, 37. Britton was assistant regional director for the Census Bureau's New York office. Martinez was an automation specialist in the same office.
Both Britton and Martinez worked at the bureau's main New York office at 26 Federal Plaza, whose 50 employees have yet to return to work because the building is still off-limits to most agencies, according to Marvin Raines, assistant director of Census field operations in Washington.
"Emotionally, we're trying to deal with the impact of all this on the work we still have to do," said Raines.
Besides grieving over the loss of two of their fellow employees, some Census employees are skittish about returning to work at 26 Federal Plaza, Raines said. "[The Census office] is on the 37th floor, and it's one of those high-profile government buildings that could easily make it a target. That creates a sense of uneasiness among employees."
Counselors have been phoning Census employees at home, according to Raines.
With offices at 26 Federal Plaza still mostly closed, many agencies have set up shop at alternate sites around town. The IRS will move a large number of its employees who work in the facility to its office in midtown Manhattan Tuesday, according to a spokesman. The Social Security Administration has also moved a team of employees to an agency office near Grand Central station in midtown.