The Committee to Protect Journalists is investigating the circumstances of the case to determine whether the journalist's murder is connected to his work.
Cantoneros, 32, who frequently criticized local officials for alleged corruption and illegal gambling on his talk radio program on DXAA-FM, was returning home around 1:30 a.m. when he was attacked by as many as three gunmen, according to local news reports.
Cantoneros was clutching his own .45-caliber pistol when he was found, and he appeared to have fired back at his attackers, according to ABS-CBN, quoting police. Cantoneros' colleague, Robert Baguio, told radio DZBB that the journalist identified his assailants before undergoing surgery, according to Inquirer News Service.
Cantoneros' colleagues told reporters that the journalist had received several death threats, some by cell phone text message, ABS-CBN reported.
President Gloria Arroyo's spokesman Ignacio Bunye called for a full investigation. "We condemn this [attack] and we expect the Philippine National Police to do its job in investigating this crime," Bunye told DXMM radio, according to Agence France-Presse.
The journalist's murder comes just days after another radio broadcaster, Nestor Seguismundo of DZXE's Radyo Tirador in Ilocos Sur in the central Philippines, survived an apparent assassination attempt. Seguismundo, whose hard-hitting broadcasts have criticized provincial authorities, sustained a gunshot wound to his stomach on April 29.
Eighteen journalists have been murdered for their work in the Philippines since 2000, making it the most murderous country in the world for journalists, CPJ reported this week. Many of them were rural radio broadcasters who were targeted for their reporting on corruption and crime. Six were murdered in Mindanao alone, a region rife with crime and lawlessness. No one has been convicted in any of the murders. Violence against journalists is so pervasive, Philippine police officials went as far last year as suggesting journalists arm themselves.
Read "Marked for Death," CPJ's analysis of the most murderous countries.