The four men accused of conspiring to bomb two Jewish sites in the Bronx and shoot down military aircraft in Westchester appeared before a judge Friday for a preliminary hearing.

James Cromitie, David Williams, Onta Williams and Laguerre Payen, of Newburgh, pleaded not guilty Wednesday to a slew of conspiracy charges, including conspiring to use weapons of mass destruction and acquire and use anti-aircraft missiles to attack planes at the Stewart Air National Guard base in Newburgh.

The four suspects were taken into custody May 20 after allegedly planting what they thought were bombs in front of Riverdale Temple and Riverdale Jewish Center in the Bronx. Investigators say the mock explosives were provided to the suspects by an FBI informant.

During Friday's hearing at the White Plains Federal Courthouse, Payen's attorney claimed her client could not have be involved in the alleged plot because he suffers from a bipolar disorder and schizophrenia. The lawyer also added that Payen cannot stand trial due to his condition.

Prosecutors insist they have hours of recordings in which the suspects, including Payen, can be heard discussing the details of the terror plot.

The suspects' next court appearance is scheduled for Sept. 17. If convicted, the four men face life behind bars.