Police are looking for a man they say is responsible for stabbing and killing a 21-year-old Brooklyn man early Sunday.

Kevin Rivera was found with a stab wound to the chest around 2:17 a.m. after officers responded to a Bushwick apartment to a call of an assault with a knife. He was taken to Woodhull Medical Center and pronounced dead. 

Police are looking for Nicolas Dias, 81, who is wanted in connection with Rivera's death.  

Police sources told the Daily News that Rivera may have been stabbed to death by his girlfriend’s grandfather following an argument.