BEIJING >> The scandal has all the makings of a classic takedown in a corrupt city: Crusading journalists publish allegations of a security firm abusing people on behalf of crooked officials. Police launch an investigation and arrest the firm’s top officers. Politicians hold their breath, hoping they don’t get named.

Except, this being China, the officials suspected of availing themselves of the paid thugs haven’t had much cause to squirm. When Beijing-based financial magazine Caijing ran a report this month describing Anyuanding Security Services as a de facto mercenary police force that snatched law-abiding citizens off the streets and locked them up in secret “black jails,” it wasn’t the security firm that was immediately raided by police. It was the magazine.

The police move, an attempt to get the magazine to reveal sources, followed a practice that’s long been hidden and denied by authorities, observers said.

For years, human rights workers have said people who journey to Beijing with complaints of injustice often wind up in secret makeshift prisons. But the government has repeatedly and flatly denied the existence of the black jails.

Then the headline-grabbing raid at the magazine caught people’s attention; it got the Internet buzzing. The original story was quickly scrubbed from Chinese websites, but it still hung in the air, demanding an answer.

It came this week, when state-run news media reported that police had launched an investigation of the security firm. The manager and chairman of Anyuanding had been arrested, the China Daily said.

What’s more, journalists at the magazine told reporters that the police apologized for the raid.

“Under these circumstances, the police will face a lot of pressure if they don’t investigate,” said Xu Zhiyong, one of China’s most prominent human rights lawyers. “That’s why they finally had to do something.”

According to the Caijing story, the security agents wore outfits resembling police uniforms, snatched people off the streets and sometimes physically abused them in unofficial prisons.

They were hired by regional and smaller-city leaders eager to keep their reputations clean in Beijing by silencing complaints from their home districts. The security firm was paid to round up the would-be petitioners before their gripes could be recorded, then transport them back to their hometowns.

And business was booming. Profit more than doubled to top $3 million in 2008, the magazine reported.

People expressed outrage online over the report and the government’s attempt to squelch the journalists. Other publications soon took up the story. The Southern Metropolis Daily reported that officials paid as much as $45 a day for the capture and detention of a citizen.

Even the state media got involved, with the New China News Agency calling for the arrest of local officials along with company executives. (That story also was scrubbed from the official news website soon after it was published.)

Critics from all corners said the people who enlisted the company’s services should not remain unscathed.

“If you only investigate this company and do nothing to the local government officials, it’s not effective,” said Pu Zhiqiang, a lawyer who represents Caijing. “They’re not getting at the origin of the problem.”

Liu Jiandong, a 58-year-old retired telecommunications employee from the southwestern city of Kunming, said he was detained by Anyuanding last year. Reached by phone this week, Liu was still seething with indignation over how he said he was treated.

Following a time-honored tradition of seeking redress in the capital, Liu journeyed to Beijing last year to complain of mistreatment at the hands of his boss.

Liu said he was detained by police while trying to lodge a complaint in the government telecommunications headquarters. He was then taken to an office belonging to Anyuanding and handed over to uniformed guards employed by the firm, he said.

In the company’s custody, he and dozens of other petitioners were held in a secret jail on the outskirts of Beijing for 12 days, he said. Conditions were squalid, and he said he saw other prisoners beaten, though he was not.

Eventually, guards took him to a train station and escorted him home.

“I’m very, very angry,” he said. “I’m going to sue this security company.”

The company’s website has been taken down, but a cached version stored on Google shows a group of improbably underfed-looking men in black. The website claimed a 3,000-person staff responsible for guard duty at shopping malls, office buildings and high-end villas.

“We have contributed positively in ensuring the safety of the customers and assisting the police to maintain social order,” the website said. “And we have won recognition from all sides of society.”

Recruitment materials for the firm promise a salary ranging from $134 to $224 a month, minus $30 for uniforms. All applicants should be tall, with no tattoos, psychological issues or contagious diseases.

They should also share “progressive” political thinking. As people here understand, that means it should be in line with that of the government.