A Manhattan judge let one of the two men accused of plotting to attack New York City synagogues continue to walk free Wednesday — after prosecutors asked for the second time in two weeks that he be held in jail without bail. Assistant District Attorney Edward Burns argued that disturbing new facts in the case of Matthew Mahrer, 22, were reason enough to keep him locked up after his family paid $150,000 in bail to set him free on Nov. 21. “We now know that Mahrer, [accused accomplice Christopher] Brown and [a] third individual, drove to Pennsylvania on November 18 to purchase a firearm. That individual who drove with them has since been arrested by federal authorities,” Burns said. Prior to his arrest on Nov. 19, Mahrer had been sending an unnamed jailbird payments for the gun he and Brown planned to use in the would-be attacks last month, the prosecutor said. Burns added that Mahrer has continued to financially support the incarcerated person — who was locked up for 3 1/2 years for criminal possession of a weapon — even after his own arrest.