The victim, Ariel Pineda, 40, an alleged Sigue-Sigue Commando gang member and resident of the LRC Compound, died from a gunshot wound in the chest. His body was found in an alley in Sta. Cruz.
Investigators Paul Dennis Javier and Virgo Villareal said the victim was a known drug user.
A 15-year-old girl, who witnessed the shooting, told police the suspect shot the victim at close range.
"Nakita ko na lang po na biglang binaril ni Kuya Albert si Kuya Ariel (I saw Kuya Albert shoot Kuya Ariel)," the witness said.
She immediately called the attention of her neighbor, PO2 Melchor Nuñez, who rushed to the scene. The suspect fled after seeing Nuñez.
Residents said the victim received his supply of illegal drugs from the suspect. Police said they believe that a double-cross could have been the motive for the slaying.
A barangay official provided police the identity of the suspect.
Alberto Itulid, a resident of Natividad street in Sta. Cruz, they said was a notorious drug pusher in the district.
A follow-up team of operatives are now hunting down the suspect.