A German man and his dog have offered up their services to help concerned parents sniff out whether their children are taking illegal drugs.

Reiner Reuther and his dog Thor search flats, bedrooms and cars for controlled substances such as cocaine, marijuana and ecstasy – but leave it up to the parents to decide whether or not to alert police. "We are just there to bring people certainty," Reuther told the Guardian.

In one case, Reuther was called in to help after a set of parents became suspicious that their daughter was using drugs. He searched the home while the daughter was out for a few hours and quickly found a stash of cocaine hidden in a jumper in the dirty washing. The discovery helped the parents plan a discussion with their daughter, he said.

But another case turned out rather differently when the parents called the police on their son who then faced criminal proceedings and lost his apprenticeship.

"Private dog handlers are not subject to this obligation," said Reuther, emphasising that his services were 100% anonymous. "We advise the parents principally to get drug counselling, they can get a psychologist for the children. [But] the parents can decide how they want to proceed."

As well as working with parents for around €95 (£82) per search, Reuther and Thor also track down drugs at businesses including nightclubs, and at some private schools. "The schools have problems, that's widely known, but it's not talked about," he said. "Drugs are a problem that is always there and it's a topic that is mostly covered up."

After working as a hotelier for 25 years and training dogs on the side, Reuther wanted to work with the animals full-time. He got the idea for his business while training as a dog handler at a police academy in the US.

He said that in America, searches for drugs at schools happened routinely. He finished his exam to become a sniffer-dog handler and bought Thor back to Germany. After setting up his website and getting Thor accustomed to his new home, they went to work.

"I wanted especially to help parents so they could get certainty about their children and better react to get them help," he said.

In America and England, he said, people were much more open about drugs. "In Germany, people speak about it behind closed doors … but like I said, the problem is there and it's not small.

At the moment Reuther and Thor are a one-man, one-dog operation, but Reuther said he hoped that would change. "We work alone, but the business is being built up," he said.