Adolfo Echeveste, manager of the Census 2000 office for eastern metro Phoenix, said the raid at a house Thursday in Mesa, Ariz., could interfere with efforts to count people who may already fear the government.
"The timing of it was most unfortunate," Echeveste said in an interview with KTAR-AM. "We in the federal government have been spending millions upon millions of dollars to point out that everyone should be counted, whether they're here legally or otherwise."
The U.S government conducts a census every ten years. Past censuses have missed a disproportionate number of minorities, poor people and immigrants.
But the INS said the raid was in line with policy since it stemmed from a police tip.
"We have no intent to plan operations in areas where the census is being conducted. But if we get calls from police, we are obligated to help them," INS spokesman Russell Ahr told The Arizona Republic.