Jose del Castillo, a city immigration attorney and former chairman of the Hartford Redevelopment Agency, admitted in federal court Friday that he falsified federal documents to assist illegal immigrants along the path to legal residency. Del Castillo, 48, pleaded guilty in U.S. District Court to one count of federal document fraud, a felony that could net him up to 10 years in prison and a fine of $250,000.

Del Castillo was indicted in late 2006 on nearly two dozen counts of document fraud for filing immigration forms with state and federal officials saying his clients had legitimate job offers as cooks and hosts at Mamacita's at the Forge Restaurant, a Broad Street restaurant he owned earlier in the decade.

The forms, which del Castillo accepted payment for and filed in 2001 and 2002, contained assertions that del Castillo knew were not true, such as that the applicants were qualified to do the work and that hiring them would not affect legal workers, according to federal prosecutors.

In a nearly hourlong hearing before Chief U.S. District Judge Robert N. Chatigny, a week before his case was scheduled for trial, del Castillo pleaded guilty toknowingly falsifying and filing paperwork for a woman living in Poland to begin the citizenship process. The action was taken without her knowledge or consent.

Federal sentencing guidelines contemplate between 12 and 18 months in prison and anywhere between a $3,000 and a $30,000 fine, Chatigny said. Del Castillo is scheduled to be sentenced July 28.

After his sentencing, del Castillo could face disbarment. Del Castillo has already been twice reprimanded by the Statewide Grievance Committee of the Statewide Bar Counsel.

The case against del Castillo goes back to early 2001, when windows in federal law had given illegal immigrants with an employer or family sponsor the chance to pay a $1,000 penalty, seek a green card while on U.S. soil, and possibly achieve citizenship.

The process began with the filing of paperwork with the state Department of Labor.

In March 2001, del Castillo opened Mamacita's, his agreement says. On April 30, 2001, he filed roughly 100 applications for clients, records from the labor department show. He filed more applications later in 2002.

Of those 2001 applications, 14 were for people to work at his Frog Hollow restaurant — nine cooks, five hostesses. They were supposedly to do the full-time work that he said U.S. citizens wouldn't do.

Records show the applicants came from Colombia, Germany, Brazil, Peru, Venezuela, Ecuador, Mexico and Poland.

In their indictments, federal prosecutors alleged that several of the applications del Castillo filed for people to work at Mamacita's were fraudulent. So were applications he filed for clients to work in at least one other area restaurant.

Del Castillo's admissions drew a sharp rebuke from one prominent immigration attorney.

"You can't say, 'I'm only trying to help somebody,' when you flat-out lie to the United States government," said attorney Joseph Tapper, former chairman of the Connecticut chapter of the American Immigration Lawyers Association. "That is an unethical, illegal thing for a lawyer to do and there are reasons for our rules."

"Millions of other people would have loved to get into this country," Tapper said. "But dozens and dozens and dozens of ethical practitioners refused to file cases for people who didn't have a legitimate claim."

Hope Seeley, del Castillo's attorney, declined comment.

Contact Jeffrey B. Cohen at jcohen@courant.com.