His alleged victims were new to this country and in need of immigration documents. They undoubtedly trusted him: a man who claimed to be an immigration official capable of providing green cards and working visas in exchange for cash. Yesterday, police arrested the individual they said impersonated a federal official and bilked more than 40 people out of nearly $300,000.

Prosecutors indicted John Nevarez, 54, on charges of criminal impersonation, scheme to defraud, grand larceny, and possession of forged documents. Between October 2005 and April of this year, officials said, Nevarez posed as an Immigration and Naturalization Service employee, and promised immigration papers to more than 40 unsuspecting victims.

“He was selling just the word,” the commanding officer of the police department’s Impersonation Unit, Lieutenant John Zerillo, said. Preying on immigrants from South and Central America, Lieutenant Zerillo said, “He never delivered any items whatsoever. When the people came back, he would either stall them or threaten them.”

Officials said Nevarez, who ran his cash-only business out of an East 110th Street storefront, met his victims through a Bronx pastor who did not know about the alleged criminal activity. On average, victims paid him $8,000 for green cards, although one individual paid $22,000 for his services. In some cases, the victims did not meet Nevarez directly, but transferred money through the clergyman, whom prosecutors did not name. The pastor legitimately helps immigrants get access to social services and is not suspected of wrongdoing, prosecutors said.

Prosecutors said Nevarez began his scheme about a month after being released from parole in 2005, following a stint in state prison for burglary. Police said he had been arrested 28 times between February 1976 and November 1998 on charges ranging from robbery to drugs. He was convicted on four misdemeanors, in addition to the burglary conviction, prosecutors said.

In addition to yesterday’s charges, prosecutors said they believe Nevarez has more victims, whom investigators will seek out. “There are undoubtedly more cases that we have not uncovered,” the Manhattan district attorney, Robert Morgenthau, said.

Yesterday, immigration advocates said fraudulent immigration relief is a rampant problem, particularly during an intense national debate over immigration. In a recent high-profile case, a former immigration officer in New York, Phillip Browne, was arrested and charged with running a million-dollar green card scam.

“Given language barriers and also the amount of hope and desperation around community members seeking immigration relief, it’s a particularly vulnerable population,” the senior staff attorney at the New York Immigration Coalition, Avideh Moussavian, said.