Mendoza, 31, fought back tears as she recalled watching the disaster unfold on television from her modest home in Jonacatepec, a central Mexican farming town. Her husband, 33-year-old Juan Ortega, delivered London broil and Tiramisu to business executives at the Fine & Shapiro deli in the mall below the structures.

"I kept trying to call, but I couldn't get through," she said.

Ortega is one of scores of undocumented workers still missing -- and one of 28 from Mexico. Yet the number of busboys, janitors, delivery men and others with low-paid jobs who were lost in the World Trade Center may never be known. Many employers know little about their illegal help, and some families may not even know that they are gone or are too scared of immigration officials to fill out a missing person's report.

To aid the investigation, the consulates of Guatemala, Mexico and Colombia say they have placed ads in their nations' newspapers asking relatives to report those who have disappeared. The Mexican consulate has also placed ads on Spanish-language radio, television and newspapers in New York.

In a prepared statement, Immigration and Naturalization Commissioner James Ziglar urged "the immigrant community to come forward," and assured "everyone that the INS will not seek immigration status information provided to local authorities in the rescue and recovery efforts."

However, Asociacion Tepeyac, an advocacy group for illegal immigrants in New York City, says there is another basic problem: Many employers fear INS fines if they report a missing illegal worker.

"We would like the INS to waive sanctions to encourage employers to come forward with information about employees," said Joel Magallan, the group's executive director.

Ortega is part of a wave of Mexican immigrants to New York that has grown exponentially over the past decade. Hundreds of foreigners from some 40 nations disappeared on Sept. 11 after the attacks on the World Trade Center. Although city statistics show that 420,000 undocumented immigrants live in New York City, advocacy groups say the number is closer to 500,000.

Mendoza hasn't seen her husband since he left Mexico for "economic reasons" about 20 months ago. At home, he eked out a living by selling socks and underwear at street markets. Unable to support his wife and three childrens -- ages 9 to 13 -- Ortega crossed into the United States, spending about a week trekking in the desert before finally arriving in New York.

His earnings and tips at the deli allowed him to send $400 every month to support his family, including his mother and a disabled brother-in-law. He would also call home twice a week from the small Brooklyn basement apartment that he shared with a friend.

"Juan was a hard worker and an optimist," said his brother, Vicente, who accompanied his sister-in-law to New York in a trip sponsored by the state government of Morelos. "He always said, 'You have to live today like it was your last.' "

In the days following the tragedy, Mendoza hoped to find her husband alive. Now, three weeks later, she has accepted his fate.

Just last week, New York authorities declared the nearly 5,000 missing persons to be officially dead, even though their bodies have not been recovered. The decision allows family members to acquire death certificates needed to claim benefits.

Mendoza also hopes to receive financial aid and stood in line for hours Monday with other families at an emergency city-run center in the initial step toward claiming relief. She communicates through a translator provided by the Mexican consulate with U.S. officials who have requested translated documents.

"They asked me for his birth certificate and our marriage license, which I have in Spanish but not in English," she said.

It is still unclear what benefits she will be eligible for. Although New York Mayor Rudolph Giuliani has pledged to use "whatever influence I have" to help relatives of illegal workers, the state Crime Victims Board reportedly turned away last week 15 undocumented workers when they were unable to provide social security numbers.

Yesterday, however, board spokeswoman Caroline Quartararo said the undocumented would need only a signed affidavit from a family member.

In addition to dealing with annoying red tape, Mendoza must cope with the realization that she will never see her husband again.

"I would give it (benefits) all up to have my husband back," she said.