Authorities are continuing to negotiate with a man who they say is barricaded inside his Eastchester Road home.The NYPD, SWAT personnel and hostage negotiators have been at the scene since Tuesday afternoon. Police say the suspect hung an American flag upside down in his window, a symbol for distress. According to police, he threatened to blow up the house if authorities tried to enter. Sources have identified the suspect as Joe Principe, a retired corrections officer and a military veteran.Officials have not yet said what initiated the standoff.