On the inside of the forearm of 37-year-old Rith* are two small circles of scar tissue. Stab wounds. A consequence of life as an undercover freelance police informant or “secret agent”.

Rith is not his real name. A tattered and creased laminated letter he keeps folded in his wallet bearing the seal of Phnom Penh Municipal Court explains that his work must be kept secret.

However, under the cover of anonymity and with permission from his commune police handler, Rith provided an intriguing insight into a precarious and ethically fraught crime-fighting tool that regularly places its practitioners in harm’s way with little financial reward.

Rith began working as an informant in 2007. A relative at the Interior Ministry said he could make a little extra on the side passing information about criminals to the police. This suited Rith perfectly as it was something he had already been doing in his own neighbourhood, he said.

“My neighbourhood used to be dangerous, but I showed the police who to arrest,” he said.

The Phnom Penh Municipal Court issued him with the “incitement letter”, authorising him, under the supervision of police handlers, to buy drugs from dealers around the city in order to gather evidence for the police.

For the past nine years, he has been purposefully rubbing shoulders with the capital’s drug users and dealers to gain an insider’s perspective on Phnom Penh’s underworld. His work is a perpetual exercise in trust building, gaining the confidence of characters to whom the police might otherwise not have access.

“I gain dealers’ trust by buying them food and drink,” he said. “Sometimes they return the favour, too.”

But when criminals suspect they have a snitch in their midst, it often ends badly for Rith.

The two scars on his arm were inflicted with a samurai sword when he failed to win the trust of drug dealers in Phnom Penh’s notoriously meth-ridden Boeung Chhouk neighbourhood.

“There have been many times people have suspected me,” he said.

Sometimes, gaining people’s trust means dabbling in the drugs they use.

Dara*, police chief of the commune where Rith lives, said it was not unusual for informants to break the law and, to a point, it was standard practice for police to look the other way.

“Our active agents are small-time drug users,” said Dara. “If they commit serious offences such as mugging, robbery or breaking and entering, we cannot excuse this. But if they just steal clothes or shoes, we just close our eyes. But we educate them not to do it often, otherwise we cannot put up with it.”

But National Police spokesman Saran Kamsoth insisted police never used drug users as informants.

“Secret agents are not allowed to use drugs,” said Kamsoth. “We don’t use people who commit crimes.”

Rith said that while he had used in the past, he now only takes drugs when his job requires it, behaviour he said is sanctioned by his handlers.

“I used to use crystal meth; I still use it to get close to people,” Rith said. “It makes me not sleepy – I couldn’t describe the feeling exactly, I only use a little bit – it’s good for sobering up when I’m drunk.”

Relying on drug users as part of the intelligence gathering process presents both ethical and practical concerns for law enforcement. David Harding, who has worked with Cambodian drug users for over a decade, said there was a danger that the practice risked enabling drug users.

“You risk locking them into a lifestyle of addiction. That could be perceived as being ethically dubious. They could be locked in already, but if you’re paying them, then there’s no impetus for them to stop,” said Harding.

Citing the need to protect their methods, senior National Police officials refused to divulge how many informants they had, or even where they get the money to pay them.

“We cannot say how many agents we have because it’s like an army; we cannot tell the size of our army or what kind of weapons we have,” said National Police spokesman Saran Kamsoth.

Transparency International Cambodia’s executive director Preap Kol expressed concern at the use of private citizens as paid informants.

“Hiring civilians as secret agents to undertake this kind of job costs less money but poses some risks, especially if the ethics and integrity of these individuals are not taken into account and without proper oversight mechanisms,” Kol said in an email.

“Informers are a very dangerous breed of people,” said James McCabe, a former Australian police detective who now works closely with the Cambodian National Police in tackling crimes against children as head of the Child Protection Unit.

“They’re giving you something, but they always want something in return, that’s always been the conflict,” he continued, adding the caveat that informers constitute “a great investigative tool and an asset”.

McCabe said people generally have one of three motivations for informing: reward money, a reduced sentence or preferential treatment.

“Cases can go terribly wrong if you rely solely on the word of someone who’s potentially trying to ingratiate themselves or get vast financial reward,” said McCabe.

Vast financial rewards, however, are unlikely for Cambodian informants. One commune police chief said that rewards could go as high as $150, but Rith has never earned more than $100 per case and Dangkor district police chief Chim Sitha gave an example figure of 200,000 riel (roughly $50).

However, there is a financial pressure on informants like Rith, who barely scrapes by supporting his family with his work.

Human Rights Watch’s Asia division deputy director Phil Robertson said in an email that paying informants on a case-by-case basis “raises the concern that these informants have an interest in manufacturing cases to get paid”.

However, the head of the National Police’s anti-drug department, Mok Chito, insisted that measures existed to ensure the accuracy of informants’ tips.

“We don’t just get information from them and go to arrest the suspect right away. We have to investigate and look at the evidence they present, along with many other procedures,” Chito said.

Rith comes from a military family. His father was a lieutenant-colonel, having joined the pro-Hanoi Khmer People’s Revolutionary Armed Forces in 1979. Rith’s mother served, too, and in 1993, Rith joined the Cambodia People’s Armed Forces himself.

“I don’t want him to do this work; I’ve been to too many battlefields,” Rith’s father said before hoisting up his left trouser leg to show a thick-stitched scar he said conceals a bullet lodged in his thigh.

Neither father nor son had much luck as soldiers. Rith’s father fell on hard times and sold his commission to another man, forfeiting his army pension. Rith served for eight years, taking shrapnel to the head in 1997 from an exploding Khmer Rouge rocket-propelled grenade, but had not even made corporal by the time he was declared unfit for service in 2001.

Now the pair, along with 20 family members, share a cobbled-together shack on land they say is currently being targeted for development. When reporters came to visit them at home, the power was off. They usually tap their neighbour’s, who they had been unable to pay that morning.

Each month, the family scrapes by on Rith’s army pension, which amounts to less than $100, his shifts as a petrol station security guard, which brings in another $120, and whatever he makes from his work as an informant, which is normally not much.

Each case he works earns him between $30 and $100 but takes about five to six months to complete. Some days, one or two cases come through, sometimes he goes a whole month without one paying off.

“I’m an honest secret agent, that’s why I’m poor,” said Rith between slurps of chicken soup at a crowded lunch spot in his commune last month.

Not all informants are as honest as Rith though.

The letter issued by Phnom Penh Municipal Court attesting to Rith’s status as a “secret agent” permits him to buy drugs for the purposes of gathering evidence but specifically prohibits him from selling them. However, Rith insists many of his colleagues do just that.

In January, another informant suddenly appeared flush with cash. Rith made some inquiries and discovered she had been using her cover as an informant to deal drugs and run a gambling den. When she got wind of Rith’s investigation, she set a gang of youths on him.

“I filed a complaint against her with the police for attempted murder, but they reduced it to violence,” Rith said, adding he believed they did so because she was an informant.

Rith has terrible luck. In the biggest case he ever had, another informant beat him to the reward money.

By chance, he met someone working at an enormous Kampong Speu meth lab. He was excited to have stumbled upon such a big case, “But I failed to inform the police before the other agents did.”

Another time, he and his wife were playing cards with three others at the Stung Meanchey home of a drug user when police burst through the door, arresting all five of them. Rith and his wife had been there to gather intelligence, but were sent to jail with the rest.

Rith shared his cell with three others without access to a telephone or a mattress to sleep on. What food he had to eat was donated by relatives. On the third day, the court confirmed his status as an informant and released him and his wife.

Rith believes life would be better for them if he was drawing a police officer’s salary.

“I want to be a policeman to help solve crimes so society sees me as a good person,” he said. His handlers at the municipal police department promised there would be a job in it for him if he got results as an informant, he said.

Commune police chief Dara believes that is unlikely to happen. “Some people have what it takes to be a policeman. For Rith, he is old and poorly educated, so it’s hard to include him,” said Dara.

On consideration, Rith is not convinced either.

“The municipal police promised me a job if I got results, but maybe they just cheated me,” he said.

* Names have been changed to protect the identity of the police informant.