A chance meeting between a confidential government informant and a former Wal-Mart stock clerk will be a key piece of a criminal trial that begins this week for four men accused of attempting to bomb a Riverdale synagogue last year.

Federal prosecutors claim the meeting in the parking lot of a mosque in Newburgh, N.Y., in June two years ago led to law enforcement uncovering a homegrown terrorist plot. It culminated in the arrests 11 months later as part of a sting operation of James Cromitie and three other men moments after they allegedly planted explosive devices outside a synagogue and a Jewish community center in the Riverdale section of the Bronx, prosecutors said.

Defense attorneys have countered that the plot was “fake”—that it was completely orchestrated by the informant, not Mr. Cromitie, a high-school dropout who had served jail time on drug charges. The defense lawyers say the informant acquired the nonworking explosives, chose the targets and wired the devices on the night of the attack, all in an effort to entrap the men.

Jury selection begins Monday in federal court in White Plains, N.Y., in the trial of Mr. Cromitie, David Williams, Onta Williams and Laguerre Payen on charges of attempting to use weapons of mass destruction, conspiracy and other crimes. Onta Williams and David Williams are not related. The trial is expected to last five to eight weeks.

The trial comes about six weeks after Faisal Shahzad, a naturalized U.S. citizen originally from Pakistan, allegedly attempted to set off a crudely made car bomb in Times Square.

A lawyer for David Williams declined comment. Lawyers for the other men didn’t return phone calls seeking comment.

The Riverdale case will likely pivot on several conversations between Mr. Cromitie and Shaheed Hussain, an informant for the Federal Bureau of Investigation, according to legal experts. Many of those conversations were recorded or videotaped at a house the FBI had rented in Newburgh.

“Given the fact that some of the statements the defendants allegedly made are so ugly and so hateful, there’s a very real possibility the basis of their conviction will be the drivel that came out of their mouths,” said Ronald L. Kuby, a criminal defense lawyer not associated with the case.

Prosecutors have alleged that Mr. Cromitie approached Mr. Hussain outside of the Masjid al-Ikhlas Mosque in Newburgh in June 2008. His alleged comments over the next two months to Mr. Hussain about wanting to “do something in America” so concerned authorities that they began recording his conversations and eventually set up the sting, prosecutors said.

Susanne Brody, a lawyer for Onta Williams, has argued in court papers that Mr. Hussain’s urgings were the only reason the purported plot ever occurred. She described him as a convicted fraudster and professional informant.

Mr. Hussain pleaded guilty to an unlawful transfer of an identification document in April 2003 as part of a cooperation agreement with federal prosecutors before becoming an FBI informant, according to prosecutors.

A spokesman for the U.S. Attorney’s office declined to comment about Mr. Hussain.

(Source: Wall Street Journal)