Firefighters are investigating the cause of a blaze that killed a woman in an apartment at 250 West 104th Street yesterday before 6 p.m. The Post reports the woman's mother attempted to rescue her 48-year-old daughter but the daughter's bedroom was "mysteriously blockaded, according to neighbors who responded to the mom's cries for help." (NY1 says the door was blocked with suitcases.) The daughter died of smoke inhalation; more than 60 firefighters fought the fire.