An elderly man in Guizhou, China, fell to his death in a lift shaft last month after his son-in-law unlocked and opened the doors to the shaft.

Footage of the incident, which occurred on Sept 24, began circulating on Weibo last Friday (Oct 5).

In the video, the pair are seen standing at a lift lobby with two sets of lift doors, waiting for one of the lifts to arrive.

The son-in-law, later identified as a man surnamed Zhou, walks to the doors of the second lift shaft, unlocks them with a key and manually pries the doors to the empty shaft open.

His father-in-law calmly walks past him into the empty shaft and falls in. Mr Zhou appears to try and catch him but fails to do so.

The footage ends with Mr Zhou peering down the shaft, while a security guard runs over with a torchlight.

The footage left many netizens confused, with some wondering if Mr Zhou's father-in-law had intentionally stepped inside, or whether Mr Zhou had tried to murder him.

Chinese media outlet Shanghaiist blamed Mr Zhou for being "reckless" and "impatient" instead of waiting for the lift to arrive.

A report by Sina, however, gave another side to the story.

According to news and lifestyle content site AsiaOne, the Sina report said that Mr Zhou had spoken with reporters, who said that he had been celebrating the mid-autumn festival with his father-in-law at his home in Guizhou.

Mr Zhou said that on the day of the incident, his father-in-law had asked to visit his relatives who were living in the building.

While waiting for the lift to arrive, Mr Zhou noticed that the display panel for one of the lifts was malfunctioning, as the arrows were flickering and he could not see what floor the lift was on.

Mr Zhou, who is also an electrician in a property management company, claimed that the relative's residence happened to be his "workplace", according to the Sina report.

So, he decided to try and investigate what was wrong, and unlocked the doors to the shaft.

Mr Zhou said: "After opening the doors I was looking in and I forgot about dad, I didn't realise he was behind me."

He added that he tried to grab on to his father-in-law as the latter fell, but failed.

According to Sina, Mr Zhou's family is working with the property management office to follow up on the case.