MOSCOW — After the most recent attack on Sergei Kanev — attempted strangulation with a wire, in his apartment’s stairwell here — his editor visited him and delicately suggested that he take a six-month sabbatical from crime reporting, in America.

Kanev still chortles with delight recalling this story, as if he had been advised to take up tap dancing. He is the kind of reporter who sleeps with a police scanner beside his bed. Without work, “I would die of boredom,” he said.

And yet, his life has bent under the weight of danger. A specialist in police corruption and organized crime, he crosses powerful people and half expects to be killed for it. He has rigged up two cameras inside a bag he carries with him, so there will be a record if someone comes for him. His most recent girlfriend long since threw up her hands, so only his parents are left to beg him to quit the job.

“I understand them,” said Kanev, who is 46. “I have no answer for them.”

This has been a brutal year in Russia, not just for muckraking journalists, but also for human rights workers and a whole network of advocates who investigate public officials and extremist groups.

In the past year alone, the Committee to Protect Journalists has documented three killings of journalists and 19 work-related assaults. Amnesty International has documented one killing of a human rights worker and 16 attacks during the same period.

Bit by bit, in the era of Vladimir Putin, the ranks of people willing to hold the powerful to account are thinning. Their work is increasingly marginalized, so that most Russians never learn what corruption or human rights abuses have been uncovered. And while most do not blame the government for the attacks themselves, they say failure to investigate and punish the crimes has set a permissive, and dangerous, tone.

“This is the point where people are justifiably making decisions about the rest of their lives,” said Tanya Lokshina, deputy director of the Moscow office of Human Rights Watch. “You can’t keep approaching people and telling them, ‘I have this spare room in my apartment, and you are welcome to stay there for a couple of months.’ That is not a solution to the problem.”

Kanev is not the most obvious standard-bearer for press freedom. Stout, ruddy and a chain smoker, he could be equally mistaken for a Russian beat cop or a bandit circa 1992, the kind with “a raspberry-colored sport coat and a huge mobile phone,” said Dmitri Muratov, the editor in chief of Novaya Gazeta, where Kanev works as a freelancer.

He is also a reporter for “Line of Defense,” a true-crime show on Moscow’s Third Channel.

If the Soviet Union had lasted, Kanev might have remained what he was, a disc jockey expressing his dissent by playing Donna Summer, who had been blacklisted by the Communist Party for “propagandizing sex.”

But the deluge of the 1990s swept through his disco — two fatal attacks unfolded on his watch — and he volunteered to work the graveyard shift for a television news show. By 2005, his material had become consistently critical of the police, and he lost his job at NTV, one of Russia’s three national networks.

That is how he wound up writing for Novaya Gazeta, a newspaper known for two things: its pugnacious assaults on the Russian government, and the number of its staff members who have been murdered.

“The most dangerous thing right now is not to criticize the authorities,” said Yulia Latynina, a columnist at the newspaper. “It’s to criticize people who can kill you. The people Kanev writes about can kill. That is his problem.”

The amiable chaos of the newspaper’s office froze up in January, when a masked gunman fatally shot Stanislav Markelov, the newspaper’s lawyer, and a young reporter, Anastasia Baburova, 25.

That made five employees who had died under violent or suspicious circumstances since 2000, and the first since the investigative journalist Anna Politkovskaya was found shot to death in her elevator in October 2006.

Muratov, the editor, put two of his reporters under armed protection and instituted a policy under which any reporters with sensitive information are required to publish immediately, reducing the benefit of killing them.

Kanev, for his part, shrugs off the idea that protection is even possible.

“Look, if you want a safe job, work in a library,” he likes to say. In the meantime, he goes about his workday with what can only be called joy.

On a recent Tuesday, Kanev climbed a staircase behind a mattress salesroom and was led into an office where a tired-looking businessman recited the details of his son’s kidnapping. Kanev mopped his brow with a napkin and took no notes.

A few hours later, at the newspaper’s office, he received a gaunt, black-suited visitor from the Interior Ministry. As he walked the man out, Kanev was so happy with what he had learned that he actually began to skip down the hall, making the linoleum squeak.

“It’s like a thread,” he said. “You pull it, and pull it and pull it.”

Kanev learned about risks early in his career, when six thugs from Zelenograd tied him to a chair with speaker wire and pressed a scalding iron to his chest, demanding he surrender a videotape.

Since then, he has ratcheted up his ambitions. Early columns on police kickbacks and petty corruption have given way to detective work on Politkovskaya’s murder and on a kidnapping ring based in Uruguay — a case in which he suggests that former or current government security agents play a role. The stakes have grown, along with his sense of mission.

“We try to reach our citizens to say, ‘Look, people, it’s enough,’” Kanev said. “Let’s take back our country. This is where we were born, right?”

Last August, as Kanev was returning to his apartment, two men slipped into the stairway behind him. One wrenched away his bag, full of law enforcement documents, and the other tightened a wire around his throat, leaving him slumped in the stairwell.

His mother, Nina, heard about it from a television report, deepening her despair over her only child. She has spent years trying to convince him that the work he does is not worth the sacrifice — and that fear for his safety is wrecking her old age.

“It’s useless. It’s like hitting a stone wall with your forehead,” said Nina Kaneva, 71, a retired kindergarten teacher. “You can hit it as long as you want and get bruises and lumps if you’re lucky, or otherwise get crippled, or lose your life. How does that address injustice?

“He says, ‘Mom, if I don’t do this job, who will do it?’ And I say: ‘One man on a battlefield is not a warrior.’”

Kanev’s angry response is from the family’s history: When Nina Kaneva was 4, her father was arrested as an enemy of the people, and she never heard from him again. She hid the story, afraid that she would be ostracized.

“I tell her, ‘All your life you were afraid to talk,’” Kanev said. “I don’t want to live that way.”

And so, this bargain: He signs his name to every article. If, walking in his darkened stairwell, he senses someone behind him, he switches on the cameras in his backpack.

And when young people come to him to ask about investigative journalism, he can no longer in good conscience encourage them.

“First, I tell everything I know,” Kanev said. “Then, I say, ‘Maybe you can find another profession.’”