Four Muslim men charged with trying to blow up Bronx synagogues and shoot down military planes will be reunited at their trial with someone who was in on the alleged plot every step of the way — wire-wearing FBI informant Shaheed Hussain.

The government credits Hussain with rooting out radical Muslims at a mosque in Newburgh.

The defense has sought to portray him as a “fraudster” who lured down-and-out dupes into a phony scheme by offering them a pile of cash.

Hussain will be the government’s star witness at the trial, which is set to begin this week in Manhattan federal court.

James Cromitie, Onta Williams, David Williams and Laguerre Payen have pleaded not guilty to charges of conspiracy to use weapons of mass destruction and conspiracy to acquire and use anti-aircraft missiles to kill US officers and employees.

They could get life sentences if convicted.