The fourth trial stemming from last year's major corruption bust in New Jersey apparently will go ahead without the government's star witness.
Jury selection in Smith's extortion trial is scheduled to begin Monday.
Dwek secretly taped hundreds of hours of meetings with public officials and prominent members of Orthodox enclaves in Brooklyn and New Jersey for more than two years. Last year, more than 40 people were arrested and charged with extortion, bribery and money laundering.
Dwek has testified in three trials this year, resulting in three convictions and one acquittal.