Last Friday, as the Occupy Central protests convulsed Hong Kong, James Bang, a twenty-eight-year-old digital-strategy consultant, found himself holding down the front line in the district of Mong Kok, his arms linked with other young protesters as they fended off surging groups of attackers. The assailants shoved the protesters, spat in their faces, and shouted, “Motherfuckers!” and “Go home!” Their accents signalled to Bang that they were from Guangdong, across the border, and they wore bags slung across their chests, a style common in mainland China. He was convinced that they weren’t locals. “Hong Kong people don’t spit on Hong Kong people,” he told me over Skype. “In Hong Kong, they spit on the roads.”

Bang had been out on the streets for five days. By day two, he’d lost his job. After considering the future of his newborn daughter, he had decided that it was more important to support the Occupy movement, which was pressuring China to grant Hong Kong universal suffrage for the 2017 chief-executive election without allowing Beijing to vet candidates. When the battle in Mong Kok finally wound down, the supply station Bang had been manning was destroyed, and thousands of dollars’ worth of battery chargers, medical supplies, and food had been lost. “It was like a coördinated, planned attack,” Bang said, noting that the men were wearing identical masks. “They were basically clearing the site, removing the barricades, pulling down all the posters, and then trying to clear the people later. So they were really doing the job the police wished they could do.”

By the end of that night, eighteen people had been injured and the police had arrested nineteen people, eight of whom the authorities said had ties to Hong Kong’s organized criminal gangs, known as triads. Conspiracy theories began proliferating through the city’s vibrant social-media networks. Some people circulated photographs purporting to identify some of the attackers as undercover policemen; others sent out Facebook advertisements promising remuneration for the attacks (“Bonus: Tear down supply station $500 [(sixty-four U.S. dollars)], Successfully cause chaos $1000 [(a hundred and twenty-nine U.S. dollars)]”). The deputy chairman of the Legislative Council’s security panel, James To Kun-sun, channelled this popular outrage, accusing the government of colluding with triads, a charge that was denied by the Secretary for Security, Lai Tung-kwok. A teaching assistant at the University of Hong Kong, Kitty Ho, began to compile a database containing evidence of collusion with triads, with the aim of lodging a complaint about the behavior of Hong Kong’s official police force. When we last spoke, she had received twenty separate cases to investigate. “I just can’t let it go,” she told me over Skype, sounding weary.

The use of thugs-for-hire has some precedent in Hong Kong, especially against those whose views do not align with Beijing. In one well-documented example, this February, Kevin Lau, the former editor of the outspoken Ming Pao newspaper, was critically injured by a motorcyclist wielding a meat cleaver. The attacker left a six-inch wound in Lau’s back, deep enough to expose his chest cavity and vital organs. Eleven people were arrested, including two men picked up in Guangdong Province. Sources quoted in the local press alleged that they were hit men with the Shui Fong triad, and that each had been paid a million Hong Kong dollars (or about a hundred and twenty-nine thousand U.S. dollars) for the attack. Sometimes, gang members are simply used as messengers. The Hong Kong publisher Bao Pu told me that, in 2010, he was warned first by central-government officials, then by triad members, to abort publication of the Tiananmen memoir of then Premier Li Peng, who had been nicknamed the “Butcher of Beijing” following the uprising. Bao eventually cancelled plans to publish, citing copyright issues.

The idea that triads could be patriotic was first raised, in 1984, by Deng Xiaoping. The chief of China’s Public Security Bureau, Tao Siju, caused uproar in Hong Kong, in 1993, when he echoed those sentiments, bluntly stating, “As for organizations like the triads in Hong Kong, as long as these people are patriotic, as long as they are concerned with Hong Kong’s prosperity and stability, we should unite with them.”

In mainland China, local governments sometimes deploy thugs to evict unwilling homeowners from their property, often without proper compensation, so that the governments can cash in on the redevelopment. In 2011, a middle-aged woman named Liu Shuxiang was killed when more than a hundred workers started demolishing her apartment while she was still inside. In the hour after she was buried in rubble, she made four phone calls to the police, to no effect. Her body was retrieved two days later. State-run media said that at least eleven people had been killed that year in similar circumstances.

Thugs fulfill many other functions in China, including monitoring dissidents under surveillance or house arrest, blocking foreign journalists from visiting politically sensitive areas, and acting as enforcers to stop petitioners from lodging official complaints about government corruption. According to the University of Toronto political scientist Lynette Ong, who studies the patron-client relationship between local governments and thugs, goons are frequently used to execute decisions, especially in “the gray areas between legitimate state functions and illegitimate state policies,” such as land expropriation and forced evictions.

In economic terms, states’ use of thugs—or “violent entrepreneurs,” as the political scientist Vadim Volkov has christened them—is an efficient way to implement policy. But Ong argues that the act of outsourcing violence triggers a vicious cycle in which the state’s authority is further weakened. “The foundation of a state is that it is able to monopolize the use of violence,” Ong said, citing the German sociologist Max Weber. “So to create an alternative market where violence could be traded, the state is going down the road of delegitimizing itself, creating an alternative for the state.”

This phenomenon played out on the streets of Mong Kok as public sentiment turned against Hong Kong’s police. Five days before, officers had tear-gassed students armed only with umbrellas, plastic wrap, and swimming goggles. In Mong Kok, the police largely stood on the sidelines, watching as protesters were physically attacked and women sexually assaulted. From time to time, the officers tried to separate the Occupy camp from their opponents, but they were vastly outnumbered. Bang recalled that after he and his colleagues had sent panicky tweets that summoned hundreds more supporters to the area, the crowds began yelling “Triad police!” and “Dogs!” at Hong Kong’s finest. By Sunday, the anger had resurfaced as subversive humor; a signpost to the Central Government Offices now directed visitors to the Central Government and Triad Offices.

The ugliness of the violence—and the blatant disregard for rule of law—may have succeeded in suppressing the protests temporarily, but beneath the sly jabs lies a new crisis of trust that will linger long after the demonstrators have quieted. “I’ve lost all faith in them,” Bang said, sounding surprised by the realization. “I don’t see them as a legitimate police force any more. I don’t recognize their authority.”