Apple has announced that it will investigate the death of a Chinese woman who collapsed after being electrocuted from answering a call while her iPhone 5 was plugged in, Reuters reported.

Apple did not say if this was an isolated incident, but they would fully investigate what caused it and how to fix it.

"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," Apple said in an e-mail statement.

Ma Ailun, a 23-year-old flight attendant with China Southern Airlines, was at her home in China's western Xinjiang region last Thursday when she answered a call while it was charging. According to Xinhua News, Police said Sunday Ma collapsed from the electric charge.

Ma's sister said Ailun had bought the phone in December from an Apple store and was using the standard outlet charger to power the device.

"I want to warn everyone else not to make phone calls when your mobile phone is recharging," she posted to Sina Weibo, China's Twitter equivalent. The tweet was re-posted more than 3,000 times.

Tech experts told Xinhua News that the standard charger would only emit three to five volts. A person would only feel an electric charge at about 36 volts.

"However, if the charger or the circuit has a problem, such as a broken wire, it can lead to a shock of 220 volts," a senior physics teacher at a Nanjing high school was quoted as saying in a media report.

For that reason, Xu Xuelu, an expert with the Nanjing Appliance Repairing Association, advised any smartphone user from placing calls while the device is plugged in.

The actual cause of Ma Ailun's electrocution has not yet been determined as police continue to investigate.