The envelope produced a fine white cloud and included a vitriolic form letter, addressed to "You stupid, fucking, spic turds," denouncing Latinos as drug users and prostitutes who can't learn English.

The letter also attacked lawyers like Salinas and said that everything Latinos have achieved has resulted from white people's leadership and generosity.

It ended with a warning: "And by the way, watch out for the white powdery stuff in this envelope."

"I was scared," said Salinas, who immediately called 911. But he wasn't alone: More than 40 Latino advocacy groups, attorneys, community activists and students received the same letter in March.

None of the envelopes tested positive for anthrax. But the FBI said it was taking the threats "very seriously," treating the mailings as a violation of the federal hate crime statute.

Last year, in the wake of the Sept. 11 attacks, more than 300 fake anthrax letters were sent to abortion clinics and related facilities. A fugitive anti-abortion zealot, Clayton Waagner, was suspected.

The anti-Latino letters were signed by a self-described legal Indian immigrant. A woman with the same name who lives in San Ramon, Calif., tearfully denied that she had written the letter, and FBI officials agreed.

Christopher Arriola, president of the La Raza Lawyers Association in San Jose, Calif., which also received one of the letters, told the Intelligence Report that the intent was clear: "to degrade and dehumanize."

Meanwhile, Latino leaders were left wondering who might have been behind the threats — and what they might try next.

"What concerns me," Salinas told the San Jose Mercury News, "is that there's this group out there that's very angry. They used every negative stereotype. What else are they willing to do?"