New York, Feb 14 : An additional 500 police officers will be deployed immediately to patrol New York City's transit system both on ground and underground following four stabbing incidents within 24 hours, a top official said here. Addressing a briefing on Saturday, New York Police Department (NYPD) Commissioner Dermot Shea said the separate incidents took place from Friday to early Saturday on the 'A line' subway trains or along its subway stations, leaving two people dead, reports Xinhua news agency. Three of the incidents appeared to be connected, and all the victims appeared to be homeless, he added. According to a report by the Daily News, which cited anonymous law enforcement sources, police arrested a homeless suspect on Saturday, and recovered the knife believed to be used in the incidents. New York City's subway system has been one of the places where homeless people prefer to stay overnight or make a living, which is seen as a public safety issue. /IANS