NEW YORK: In a "bias" attack, a Sikh man lost three of his teeth after being sucker-punched in a moving train in the US by a man, who accused him of being related to slain al-Qaida chief Osama bin Laden.Jiwan Singh, who came to America 30 years ago and is an employee of the Metropolitan Transportation Authority (MTA), was attacked on the US Memorial Day on May 30, The New York Daily News reported."He was saying, 'You are the brother of Osama,", the 59-year-old Singh was quoted as saying by the news website."I said, 'I am not Osama. I have nothing to do with him!"The daily said the Sikh MTA employee was riding a train to work in Brooklyn from his home in Richmond Hill on Memorial Day when a hate-spewing straphanger accused him of being related to bin Laden and then sucker-punched him.The father of five said his son, Jasmir, 23, had also lost an eye after being stabbed by attackers in 2009 who targeted him because of his turban and traditional beard."We are Indians," he said, recalling other "Osama" slurs he's endured because of his long, white beard."Due to that ... I have suffered so much, my family has suffered so much, my community has suffered so much."Singh, an electrical engineer, said the recent attack happened about 11:30 pm and described the attacker as a black man in his late 20s.Talking about the incident, he said the car was half-empty, but the man walked right up to him and demanded he give up his seat.Singh said he was nervous, but pointed out that there were other open seats nearby.He said the man grabbed him by the shirt collar, picked him up and threw him into one of those seats."He said, 'Taliban, you sit there!'" Singh recalled. The attacker then stared down Singh - sometimes cursing him out loud, other times muttering under his breath.As the train pulled into the next station, Kingston Avenue, the man suddenly threw two quick roundhouse punches, Singh said. Both hit him square in the mouth."He said, 'This is for you, Osama!'" Singh recalled, the daily said.The New York Police Department hate-crimes task force is investigating it as a bias incident, an unnamed police official was quoted as saying.