Ravi Ragbir, an immigration advocate whose arrest by U.S. Immigration and Customs Enforcement on Thursday touched off protests in Manhattan, has been placing his hopes that he can fight deportation on his effort to vacate a 17-year-old wire fraud conviction.

Ragbir, 53, executive director of the New Sanctuary Coalition, a network of faith-based groups that advocate for immigrant rights, came to the United States in 1994 from his native Trinidad and Tobago as a legal permanent resident, or green-card holder.

But in 2001, Ragbir was convicted of wire fraud after the mortgage company he worked for was caught up in a fraud scheme and was sentenced to 30 months in prison with a subsequent stay in immigration detention. He was ordered deported in 2006.

Ragbir maintains that he was just a low-level employee at the New Jersey firm and that he was only following orders. He is fighting his conviction in the U.S. District Court for the District of New Jersey, arguing that the jury in his criminal case was given broad instructions that allowed it to convict him of conduct that wasn't fraudulent and that he received ineffective assistance of counsel at sentencing, according to a pending suit filed last year.

Until Thursday, he had avoided ICE detention by the agency's discretion, according to media reports.

According to a blog set up to support Ragbir, he was arrested as he reported to the ICE office in Manhattan for a routine check-in. His longtime lawyer, Alina Das, a professor at the New York University School of Law, told WNYC that Ragbir fainted at the office and he was taken away in an ambulance.

Media reports said hundreds gathered on Manhattan's Lower East Side on Thursday to protest Ragbir's arrest.

The New York City Police Department confirmed in an email that 18 of the protesters—including two members of the New York City Council, Ydanis Rodriguez and Jumaane Williams—were arrested.

Those arrested were cited for obstruction of justice, reckless endangerment or obstructing an emergency medical service.

Das has filed a habeas corpus petition on Ragbir's behalf in the U.S. District Court for the Southern District of New York.

Neil Weinrib of Neil A. Weinrib & Associates, a New York immigration attorney who is not involved with Ragbir's case but is familiar with it, said in an email that Ragbir's past conviction may tie the hands of the judge in his civil case, as the wire fraud conviction acts as a predicate for removal.

Weinrib said that litigants like Ragbir who have depended on prosecutorial discretion to remain in the United States are “no longer safe.”

“There is very limited relief available for this type of offense since cancellation of removal requires a showing of good moral character which, in this case, is undermined by the criminal conviction for wire fraud many years ago, which is clearly not a petty offense,” Weinrib said. “His case certainly illustrates that the current system can be very unforgiving despite the presence of significant equities.”