WU XIEYU, a Peking University student suspected of having murdered his mother in 2016, was caught by the police in Chongqing last week. Beijing News comments:

Despite being wanted for murder, Wu had been able to move around freely for three years, because of the different identities he assumed. When he was caught, Wu had more than 30 ID cards with him, according to reports, most of which he had purchased from online shops.

ID cards are of enormous significance nowadays. With an ID card, one can open a bank account, buy travel tickets, get a hotel room and any other service that requires real name registration.

The police can also locate suspects through the use of an ID card. But only if they know the ID the suspect is using.

As Wu's case shows, suspects can hide in the open using a false or another person's identity.

The key reason for this lies in people not invalidating their lost or stolen ID cards.

Most of the ID cards for sale online were stolen, and when a citizen loses his or her ID card, he or she can call the police and get a new one, but the lost one can still be used if it is not invalidated. The law requires hotels to compare the photos of ID cards with their holders, but in practice it is rather difficult for them to do so because the photos won't be changed for 10 years.

Data show that there are at least 1 million ID cards lost in China, of which a quite high percentage are for sale online. Proper measures should be taken to curb this illegal business.

Wu's case exposes the seriousness of the "black market" in the sale of identity cards should not be underestimated. Relevant governance should be systematic and long-term.

At the same time, we should also reflect on how to reduce the possibility of identity cards being "fraudulently used". In the final analysis, the reason why a "black market" for ID cards is able to exist is because when people lose their ID cards they do not cancel them.