Senior Inspector Florante Santos, Caloocan City police homicide section chief, identified the fatality as Eulogia Perez, a resident of Maypajo, Caloocan City.
Perezs grandson, with whom the suspect had a violent encounter earlier, sustained bruises and contusions on the head.
PO2 Elma Orolfo said the incident occurred at around 2 p.m. when suspect Marcelo Nocomora, 27, jobless, barged into the victims residence and armed with a hammer, hit an unsuspecting Lopez on the head several times.
Perez rushed to the aid of her grandson, but instead got the ire of the suspect who pounded away at her.
Probers said Nocomora had earlier attempted to borrow from the victims a karaoke microphone, but got a flat refusal.
Feeling humiliated, the suspect took a hammer and rushed after the victims.
Witnesses brought Perez and Lopez to the Martinez Memorial Hospital in Caloocan City, but were later transferred to the Jose Reyes Memorial Medical Center in Manila, where the widow expired while being operated on by Dr. Paul Warren Saludez.
Nocomora was arrested by PCP-7 operatives PO2 Jessie Caragdag and PO2 Halsem Riguer.
Murder and frustrated murder have been filed against the suspect. With Pete Laude