AT A NEWS CONFERENCE ON MONDAY, the municipal government of Xi'an, capital of Northwest China's Shaanxi province, announced that it had checked five samples of cables from Line 3 of the city's subway, and all of them failed to meet the required standards. People's Daily comments:

The local government has responded quickly to reports that cables supplied by Shaanxi Aokai Cable Co for the city's third subway line were substandard by launching an investigation and announcing the results. Eight suspects from the cable manufacturer are already being interrogated and the company is under further investigation.

But there are many questions that remain to be answered. According to media reports, the company received the order for the cables just two months after it began production. At that time, it was hardly known in the market but the Shaanxi Administration for Industry and Commerce put it on its list of "well-known brands". How could that happen? Was there any deal behind the scene? Was there any official involved? All these are questions that need answering.

A broader investigation is also needed, because the company supplied cables for not only the subway in Xi'an, but also the subways in other cities.

Wang Zhiwei, the head of the company, reportedly apologized to the public, begging forgiveness. But it should be noted that he is now a suspect in a very serious crime, one that might threaten the lives of tens of thousands of people, an apology cannot free him of his responsibilities.

Not only Wang, but also any powerful figures behind him, if there were any, should receive their deserved penalty. The subways concerned are used by thousands of people every day, and they need to have confidence that they are traveling safely.