A federal judge in Brooklyn excoriated a high profile defense lawyer in court yesterday after the jury handed down guilty verdicts on 12 counts of conspiring to threaten and bribe witnesses and possessing illegal wiretapping equipment. Robert Simels, 62, was defending a powerful Guyanese drug lord when he got caught on tape telling a former gang member that certain witnesses should "just fall off the face of the Earth... I'm gonna leave it to you to figure out what's going to be best to get to him." Yesterday Judge John Gleeson said that Simels crossed "a very bright line... into what is flat-out forbidden." Simels had unsuccessfully argued that when he talked about ways to "neutralize the witness" he was just talking "street" to the gang member because "Guyana is a Third World country. They sometimes speak in a very unappealing fashion, so I spoke down in a manner he would appreciate." Simels, who once represented the Jets' Mark Gastineau, faces disbarment and between 12 and 15½ years in jail. He's been put on house arrest and has to wear an electronic ankle bracelet until his sentencing in November.