A video of a police officer shooting a woman and her adult son at close range on Sunday has spread rapidly across social media in the Philippines, provoking a wave of outrage directed at the government and a police force that many say acts with impunity.

Officials said the shooting was the result of a dispute between the officer, Master Sergeant Jonel Nuezca, and his neighbors, Sonya Gregorio, 52, and her son, Frank Anthony Gregorio, 25, in the northern province of Tarlac.

In the video, Mr. Nuezca, off duty and in civilian clothes, can be seen confronting the Gregorios about their use of a boga, a homemade noisemaker constructed from PVC piping that is traditionally played at Christmastime.

But tensions quickly escalated into a fight that included Mr. Nuezca’s daughter.

After a heated exchange of words between the daughter and Ms. Gregorio, the policeman is heard in the video telling Ms. Gregorio and her son: “I will finish you now.” The officer is then seen raising his handgun and shooting Mr. Gregorio and his mother each in the head at point-blank range.

The video quickly circulated on messaging apps, social media and in the local news media, and prompted two hashtags on Twitter, #StopTheKillingPH and #PulisAngTerorista, or “the police are terrorists.”

The shootings are the latest in a series of killings involving the Philippines National Police, which is currently the focus of an international investigation. The International Criminal Court said last week it believed that there was evidence to support claims that the authorities had committed crimes against humanity as part of President Rodrigo Duterte’s bloody war on drugs in the Philippines.