Just a few months previously, the world had been fretting about the risk of a so-called Y2K bug—the fear that computers would fail to cope with the switch from dates in the 1900s to the 2000s. The damage predictions had been massively exaggerated, and the vast majority of systems were unaffected. But just as the tech industry breathed a sigh of relief, the Love Bug virus showed the true scale of devastation that could be caused in an increasingly connected world. Estimates of the damage ran into the tens of billions of dollars—much of it spent on fixing infected computers and preventing reinfection. Once it was released, the virus code could be downloaded and tweaked by anyone: within days, researchers were seeing dozens of copycat versions being unleashed.

As the news coverage became ever more shrill, investigators got to work trying to trace the source of the bug. The passwords stolen by the virus were being sent to an email address registered in the Philippines. Local police traced the email account to an apartment in Manila. The net was closing in.

After some initial questioning, they identified one Onel de Guzman, a 23-year-old computer science student at AMA Computer College, studying at the Makati campus, a grim, gray concrete building in the center of the city. The virus had mentioned the phrase grammersoft, which investigators quickly established was an underground hacking cell made up of AMA students, some of whom had started experimenting with viruses. De Guzman was a leading member.

As journalists poured into town, de Guzman’s lawyer hastily arranged a press conference so the world’s media could put their questions to the man increasingly assumed to be at the heart of global virus outbreak. De Guzman appeared, seemingly terrified, hiding behind dark glasses and holding a handkerchief over his face, covering his prominent acne scars. He hung onto his sister, Irene, who lived in the flat that the police had originally raided. Flashguns popped and news cameras zoomed in as de Guzman took his seat. But anyone expecting clarification was soon disappointed. De Guzman’s lawyer fielded many of the questions with vague non-answers.

De Guzman himself seemingly didn’t speak much English. Finally, one of the assembled media managed to ask a key question: Did de Guzman, perhaps, release the virus accidentally?

“It is possible,” mumbled de Guzman.

And that was it. There were no more questions. The press conference ended, and de Guzman’s solitary non-answer was the closest anyone got to an explanation of a virus that infected 45 million machines worldwide.

De Guzman was never prosecuted because, at that time, the Philippines had no law against computer hacking. Soon, the cameras packed up, the news crews left, and the story slipped off the agenda.

With the true author unconfirmed, suspicion fell on de Guzman’s schoolfriend Michael Buen, whose name had appeared on a previous virus, called Mykl-B. Buen denied having anything to do with the Love Bug outbreak, but his pleas were largely ignored. Most online sources still list de Guzman and Buen as the creators of the virus, either jointly or separately, and that’s how it’s been for 20 years. Until now.

The Minor Basilica of the Black Nazarene is one of Manila’s most revered Catholic shrines, and in its shadow lies the labyrinthine expanse of Quiapo market, home to everything from Hello Kitty backpacks to LED-lit Virgin Mary statuettes. It was here, acting on a tip-off, that I came to look for Onel de Guzman.

Eventually, the friendly stall-holder who remembered him directed me across town to a different shopping district. I went down another rabbit hole of market stalls, flashing the piece of paper with de Guzman’s name written on it, looking like a tourist dad who’d lost his kids. After many blank looks and suspicious questions, a bored-looking trader pointed me in the direction of a nearby commercial unit. It was empty, but after 10 hours of waiting for him to turn up to work, I finally came face to face with Onel de Guzman.