(CNN) -- It was just after 5 a.m. on a cold November morning in 2011 when Kenneth Chamberlain Sr., a 68-year-old former Marine with a severe heart condition, accidentally set off a medical alert pendant. An ambulance was dispatched to Chamberlain's White Plains, New York, apartment, though police who respond to such calls as a matter of routine arrived ahead of the emergency medical workers. Within the hour, Chamberlain, who is black, lay dying -- from two rounds fired into his upper body by a white police officer. What led to the shooting of Chamberlain is the subject of a grand jury hearing underway this month, and a matter of heated debate between the White Plains Police Department and Chamberlain's family and friends.
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The case is drawing parallels to the shooting of Trayvon Martin
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Kenneth Chamberlain accidentally set off a medical alert device, his family says
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Police say they shot Chamberlain after he came at them with a knife
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The family says video and audio recordings prove he was unarmed
Trayvon Martin
More than 206,000 people have signed an online petition demanding "Justice for Kenneth Chamberlain Sr.," with many signatories drawing similarities between the case and that of @placeholder.