Apple Inc. is investigating the death of a Chinese woman who was apparently killed using her iPhone while it was charging, the US technology giant said on Monday.

Ma Ailun, a 23-year-old flight attendant from Xinjiang, was electrocuted last Thursday when she picked up her iPhone 4 to answer a call while it was plugged in to an electrical outlet.

Apple has offered its condolences to Ma's family, and promised that it will investigate and fully cooperate with authorities in the matter, as the news spread through Chinese social media.

Ma's death first came to light when her sister posted a message on China's Twitter-like micro-blogging service Sina Weibo urging iPhone users not to use their phones while they're charging and asking Apple for an explanation.

According to Ma's sister, the phone is still under warranty and it, along with all of its accompanying accessories, has been given to police for their investigation.

Ma's case has drawn a great deal of attention on Chinese social media.

"I was so scared after reading the news," wrote "ecoeco" on Sina Weibo, "because I am always using my cell phone while it is charging."

Blogger "Snowing summer" wrote: "Regardless of Apple's responsibility, people should not use their phone while it is being charged. It's common sense."

Meanwhile, hundreds of Chinese netizens have been forwarding an article about how iPhone users should not be forbidden from answering calls while their device is charging.

The article, from the Chinese science website Guokr.com, concluded that using a cell phone while it is being charged does not raise any serious risk of electrocution.

"People using an authorized mobile phone, battery and charger will not get an electric shock, let alone be killed," the article said.

Seth Sanders, a professor of electrical engineering at UC-Berkeley, said he has never heard of such an incident before.

"Proper investigating probably would look into the charger to see if there is a problem there," Sanders said. "One possibility would be that the charger was damaged or defective."

Just as Sanders suggested, China's mainstream media have now focused on the type of charger the victim might have used.

The Beijing News said the victim's iPhone charger was likely a counterfeit.

Xiang Ligang, an industry expert in Beijing, said that based on current information, a counterfeit charger may well be the cause of the flight attendant's death.

"Counterfeit chargers usually cut corners," Xiang said. "The quality of the capacitor and protection circuit is not good. So capacitors may break-down during use, allowing a 220V current directly into phone's battery."

Ma's electrocution is still under investigation and there have been no further statements from Apple so far.

Anna Han, a professor at Santa Clara University School of Law, called Apple's response very short, but probably all they could do at this point.

"There are a lot of unknowns and third-hand information," Han said. "So there is not much Apple can do but say they will cooperate and investigate.

"There are millions of iPhone users and it seems like such a fatality is a first," she added. "Electrocution can occur from the device, but it can also occur because of the power outlet. So there can be multiple causes."