MORE THAN 6,500 RHESUS MONKEYS, Macaca mulatta, have roamed the megalopolis of Delhi in recent years. The gray-brown, pink-faced macaques—which stand at around one and a half feet, usually weigh 15 pounds or so, and can live for 25 years—reportedly have invaded homes and offices, swiping cell phones and sodas, biting children and slapping women. There are stories of them breaking into police stations, donning caps and gun holsters, and raiding hospitals, where they attack doctors and snatch IVs from patients' arms to slurp the sugary liquid. Talk to locals and you get the sense of a city besieged not by a mere species of wildlife but by a race of mischievous pixies. Everyone knows the story of the monkey who allegedly mooched booze from a central-Delhi liquor store—Aristocrat vodka and McDowell's whiskey were his favorites. Or the tale about the monkey who lovingly babysat a human child.

Cute. But as Bajwa's death showed, the pixies can turn malevolent. In April 2000, monkeys pushed a flowerpot off a rooftop, hitting an engineer on the head and killing him. In November 2007, a lone monkey ravaged the Shastri Park neighborhood and injured 25 people; a woman told reporters that the animal had reached through a hole in her roof and snatched her baby.

The cause of the monkey menace would seem straightforward: habitat loss. Delhi, with a population of 16 million, adds half a million new residents every year, many of them lured from rural villages by jobs, indoor plumbing, and McAloo Tikki Burgers. Developers clear forests to make room for the newcomers, and monkeys have to resettle in the humanized habitat. In 1989, only 10 percent of Delhi's monkeys lived in fully urban environments—as opposed to forested areas inside the city—but by last year the percentage had climbed to 78 percent. In the U.S., we know what happens when people encroach on wild areas: They get chomped by mountain lions and bears. Encroachment is also a major factor in Delhi. But, India being India, a kaleidoscopic culture straddling the ancient and modern, habitat loss is just the beginning.

For starters, monkeys aren't just animals in India. To many Hindus, the creatures are incarnations of the powerful monkey god Hanuman, a deity whose legions of fans include President Barack Obama, who sometimes carries around a Hanuman trinket. In India, devotees regularly feed monkeys in tribute to Hanuman. This teaches the monkeys to associate people with food—and to swipe it when it isn't freely given. Imagine what would happen in, say, Alaska, if residents walked around handing out salmon to grizzlies. Now imagine people building temples to the grizzly god and spinning fantastic fables about His Ursineness.

This is the situation with monkeys in Delhi, where various factors—sensational journalism, superstitious people, and crazy rumors—confuse the facts about what the animals are actually doing versus what people say they are doing. Case in point: In the summer of 2001, Delhi was supposedly terrorized by an entity known as the Monkeyman. Half simian and half human, with glowing eyes and metal claws, he attacked by night and caused terrified citizens to have heart attacks or leap off roofs. A government report later concluded that Monkeyman was a product of mass psychosis. But in a country where people worship hundreds of animal deities and demons, his existence had seemed entirely plausible.

Newspapers chip in, too, fanning the flames with headlines like MONKEYMAN'S REIGN OF TERROR IN CAPITAL GROWING DAILY! and NATION TERRORIZED BY SACRED MONKEYS. Following Bajwa's death, the news reports both frightened the public and embarrassed politicians, who could see just how Third Worldy it looked to have monkeys bumping off leading officials. So there was a call for action. Such demands had been voiced before—as far back as 2000, a citizens' lawsuit was filed to force the government to do something—but it took the Bajwa affair to start an all-out, government-sponsored capture effort. The incident was viewed as a mandate for a swift, if not fully considered, response, and 16 hurriedly scrambled capture teams hit the streets.

I arrived in January 2008, just as the roundup had reached full force, and hired a translator named Chaitanya Kabu. I had questions that needed answers. Was there really a monkey menace, and what were all its causes? Obviously, the monkeys were playing a role in the chaos, but to what extent were people part of the problem, too?