The men's main target was Danica's grandfather, 53-year-old Maximo Garcia, who had already surrendered to police a few days earlier after he was told he was on a drug watch list.
Garcia ran to the back of the house toward the bathroom as the gunmen chased and shot at him. Danica, who was stepping out of the bathroom, was gunned down, Rappler reported.
"This is so painful for us," Garcia's wife, Gemma, told the Philippine Daily Inquirer. "I would miss the nights when Danica would massage us until we fell asleep. I would miss her laughter when she teased her mother."
Gemma Garcia, who runs a small eatery, told the Inquirer she was surprised to find out that her husband was a drug suspect, saying he had never been involved in illegal drugs.
Maximo Garcia used to earn a living by driving a tricycle, a form of auto rickshaw commonly used to carry passengers in the Philippines. But he had to stop after he suffered a stroke three years ago, according to the paper.
Superintendent Neil Miro, Dagupan's police chief, told the Inquirer that 26 suspected drug dealers have been killed in the city as of Tuesday.
Nationwide, more than 1,900 killings have occurred since Duterte took office June 30, according to estimates by several media outlets. Nearly 700,000 drug users and peddlers have turned themselves in, according to Reuters.
Duterte, a tough-talking former mayor of the southern city of Davao, ran on a pledge to eradicate his country's problems with drugs. Illegal drugs, particularly methamphetamine, locally known as "shabu," have been rampant in the Philippines for decades.
The 71-year-old former prosecutor has publicly advocated killing suspected criminals, even once urging citizens to take matters into their own hands.
On Monday, Philippine senators started an investigation into the rising death toll under Duterte's administration. Witnesses, with their faces covered to protect their identities, testified about how their loved ones were arrested and gunned down by police.
Sen. Leila de Lima, head of the Senate justice committee leading the investigation, said in her opening remarks Monday that she's concerned about the spate of killings that appear to have been carried out by vigilantes, not by the government.
"What is particularly worrisome is that the campaign against drugs seems to be an excuse for some — may I just emphasize, some — law enforcers and other vigilantes to commit murder with impunity," de Lima said.
De Lima has been accused of having an affair with her former driver and authorizing him to collect money from drug lords detained in the New Bilibid Prison in Muntinlupa City, Metro Manila when de Lima was justice secretary. De Lima has denied the allegations.
Philippine National Police Director General Ronald dela Rosa reported to the Senate committee earlier this week that of those who died, only 756 were killed during confrontations with police. Dela Rosa, nicknamed "Bato," which means rock or stone, told the Senate committee that the drug suspects were killed because they resisted arrest.
"If they did not resist, they would still be alive," dela Rosa told the committee, according to the Inquirer.
The majority of the killings — 1,160 — were committed outside police operations, mostly by vigilantes, and are under investigation, dela Rosa said. He added that not all the deaths are drug-related.
International advocacy groups, meanwhile, have been vocal in opposing Duterte's policy.
Phelim Kine, deputy director of the Human Rights Watch's Asia Division, wrote Thursday about Danica May's death. Kine noted that Philippine Justice Secretary Vitaliano Aguirre defended the killings linked to Duterte's war on drugs.
"If you're in the Philippines, you will choose to kill these drug lords," Aguirre said. "Desperate times call for desperate measures. So this is what the president is doing, and we support it."
Amnesty International has called on Duterte to "break the cycle of human rights violations" and to curb his "inflammatory" rhetoric.
"President Duterte has been elected on a mandate to uphold the rule of law. It is encouraging that he spoke of honouring the Philippines' obligations under international law in his inauguration speech," Rafendi Djamin, Amnesty International's director for Southeast Asia and the Pacific, wrote in June. "But now he is in power, he needs to lend substance to those words and break with his earlier rhetoric."
U.S. State Department spokesman Mark Toner also has urged Duterte to ensure that law-enforcement officials under his administration are not violating human rights, Reuters reported.
Gemma Garcia said that her granddaughter's death has left her and her family in fear for their lives.
"We are afraid to stay here. But the problem is, where will we go?" Gemma Garcia told the Inquirer. "The killers may come back for my husband."
A kindergartner, Danica was always eager to go to school, waking up early every morning so she wouldn't be late, Rappler reported.
Maximo Garcia, according to the Inquirer, is recovering from a gunshot wound to the stomach in a hospital guarded by police officers.