The latest victim was Sgt. Carlito Alvarez, assigned at the Judge Advocate General Office (JAGO) of the Western Mindanao Command.
Police said Alvarez, who was on board his motorcycle, stopped along Mayor Jaldon street to make a call but an unidentified assassin, also on board a motorcycle, approached and shot him shortly after 6 p.m.
Police investigators saidAlvarez died on the spot still clutching his cellphone. His motorcycle also pinned him down.
The shooting incident occurred on a busy thoroughfare during the rush hour, so many people had witnessed the attack.
"It was so quick, we just heard a burst of gunfire and saw the victim fell to the ground with his motorcycle toppling over him," one of the civilians told police probers.
It was not immediately known if the assassin took the victims handgun as he was unarmed when the police found his body.
Early on the same day, Abdulgafar Uddin, an employee of the Air Transportation Office (ATO) was also gunned down few meters away from the Zamboanga International Airport (ZIA).
The attack occurred barely minutes after Interior and Local Government Secretary Ronaldo Puno passed by the area.
A Taiwanese businessman identified as Jimmy Huang was also gunned down Thursday night after making the rounds of his cellphone shops.
While police authorities are looking at various motives for the killing, ranging from personal grudges, vendetta, and robbery, residents here are worried about the unsolved killings.
Chief Superintendent Jaime Caringal, Police Regional Office 9 (PRO) director, said they will establish a "night watch" security system to avert the killings and strictly enforce the gun ban in the city.