Last week, the Xinhua news agency reported that Ma Ailun, a 23-year-old Chinese woman, was killed by an electric shock when she answered her iPhone 5 while it was still attached to the charger. “We are deeply saddened to learn of this tragic incident and offer our condolences to the Ma family. We will fully investigate and cooperate with authorities in this matter,” said Apple in an emailed statement to Reuters.

However, new details have emerged that suggest the Cupertino-based company’s product was likely not the cause of this tragedy. According to a recent South China Morning Post report, the victim may have been using an unauthorized iPhone charger. The new report also stated that the woman was using an iPhone 4, not an iPhone 5 as had been originally reported.

In an interview on China’s official China Central Television, or CCTV, expert Xiang Ligang stated that, “Knockoff chargers sometimes cut corners. The quality of the capacitor and circuit protector may not be good, and this may lead to the capacitor breaking down and sending 220 volts of electricity directly into the cell phone battery.”

Xiang also speculated that the charger may have been intended for use in a country with lower electrical voltage. The South China Morning Post notes that a police investigation is still underway.

Soon after the incident occurred, the victim’s mother posted a warning about using mobile phones while they are charging on Sina Weibo, a popular Chinese microblogging website. The post quickly went viral.

Apple has taken pains to promptly respond to any criticism in the Chinese market after it suffered negative publicity by failing to quickly respond to accusations earlier this year that it gave subpar customer service to Chinese customers. In that case, Apple eventually apologized and adjusted its warranty policy in China.