A defense lawyer says one of four men accused of trying to bomb two New York City synagogues and shoot down military planes with stinger missiles is "intellectually challenged" and has trouble understanding complex concepts.

Attorney Marilyn Reader told a court today that Laguerre Payen has "a very low borderline" IQ and is on medication for schizophrenia.

But Assistant U.S. Attorney Eric Snyder says Payen is an alert and "enthusiastic" participant in secretly videotaped discussions of the plot. Payen appears to be a Haitian citizen. The other defendants are Americans.

New York City Police Commissioner Raymond Kelly says he believes the men knew each other through prison. They have long rap sheets.

The suspects appeared in a suburban New York federal court Thursday and are being held without bail.