A former president of the American Immigration Lawyers Association, Charles Kuck, who represents some of Mr. Alcala’s old clients, says shadowy lawyers emerge any time Congress considers taking up an overhaul of immigration laws.

“Every state has a James Alcala  a man or a woman who has been arrested or indicted, or should be arrested or indicted, for engaging in fraudulent activity,” Mr. Kuck said.

Mr. Alcala’s lawyer, Susanne Gustin, would not comment. Mr. Alcala, who has been released from custody pending trial, which has not been scheduled, did not return phone calls to his law firm. If convicted, he faces up to 10 years in prison.

Court papers in the Alcala case say that the smooth-talking lawyer assured client companies that he could secure the prized H-2B visas for their workers, whom he then instructed to return to Mexico and lie to United States consul officials.

In an effort to falsely convince those officials that one illegal immigrant had never been to the United States, Mr. Alcala told the man to “show up wearing huaraches [Mexican sandals] and a sombrero,” according to the indictment. It charges the lawyer and seven other defendants, including a former Border Patrol agent and a former consul worker, with 17 counts of visa fraud and conspiracy to smuggle aliens into the United States.

The authorities say Mr. Alcala obtained at least 5,000 H-2B visas for American companies, most through fraud and forgery.Some companies that hired him  including landscaping and construction  did not know the documents they paid for were gotten illegally, said a spokeswoman for the United States attorney in Utah, Brett L. Tolman.

“There were a lot of people who were getting hurt, who were trying to do things legitimately, but Alcala never explained what would happen to them,” said Lance Starr, an immigration lawyer who once worked for Mr. Alcala, but grew suspicious that the firm was breaking the law. “He was telling people, ‘I can make you legal quickly and easily,’ and for them, it was their only hope.”