Officers responded to the Jay St-Metrotech R train just after 3 p.m., where they found a adult man, possibly in his 50s, unconscious and unresponsive.
Police say the victim suffered a fractured skull after he was badly beaten, punched in the face and kicked in the head as many as 15 times in front of the turnstiles at the station, according to surveillance video obtained by police.
The victim was taken to New York-Presbyterian Brooklyn Methodist Hospital in critical condition, and was later pronounced dead.
He has not yet been identified.
Police say the suspect was last seen boarding a Bronx-bound No. 2 train.
A person of interest was taken into custody after the NYPD released surveillance photos of the person they were looking for.
The investigation remains ongoing.
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