Suspect Patrick Laurena, 21, jobless, told police he had "blacked out" and stabbed victim Kathleen Andrada, 26, at least 15 times in different parts of her body.
Andrada, the suspects live-in partner for two years, died on the spot.
Investigation showed the incident happened at around 10:15 a.m. at the couples house located at 207 Venus street, Moonwalk Village, Phase 2, Barangay Talon.
Andrada, a cashier at a supermarket, had just stepped out of the bathroom after taking a shower when the suspect attacked her with a knife.
Househelp Arlene Reloc, 19, said in a television interview that she heard a commotion coming from the couples bedroom when she arrived from the market.
Moments later, she saw a bloodied Laurena rushing out of the room. The suspect then asked her to buy a soft drink from a nearby store.
It was her a chance, she said, to seek help from the police.
Laurena also left the house and sought refuge in a squatters area. He was immediately found and arrested by responding policemen.
The suspect admitted taking drugs, telling investigators that he was only waiting for the court order for his rehabilitation.
Laurena claimed he got enraged after his partner kept reminding him to give up his drug habit.
Police claimed Laurente was still apparently taking shabu. Investigators learned the suspect was awake the entire night, high on drugs, before he stabbed Andrada.
Laurente is now detained at the detention cell. Police are set to file a murder charge against him. Nikko Dizon