A Japanese policeman stabbed another officer by mistake during training when he used a real knife instead of a replica.

Police in Okayama Prefecture, western Japan said the incident occurred at a police academy last December while rookie officers were undergoing training in how to subdue a knife-wielding criminal.

The instructing officer acting as the criminal was supposed to use a replica but used a real survival knife. He stabbed the trainee in the chest, causing a minor injury.

The officer reportedly told police that he used a real knife to build a feeling of tension. He said he never intended to injure anyone, but stabbed by mistake.

The officer was fined 4,600 dollars by a summary court in April on a charge of professional negligence resulting in injury. He was also reprimanded by the Okayama prefectural police, but the police didn't make the incident public.

The victim left the police force in January and filed a suit against Okayama Prefecture in March, seeking about 50,000 dollars in compensation. Okayama police say they will respond in good faith.

Source: ANNnewsCH