A KFC worker has been detained for allegedly stabbing a colleague to death and injuring two other people in an apparent drunken brawl on Monday night, according to local police.

A police officer questions employees at a KFC outlet hit by tragedy on Monday.

"Our preliminary investigation shows that the murderer, surnamed Gao, was drunk and had a quarrel at home with his wife first," Liu Chunjiang, a press officer with the Public Security Bureau of Fengtai District, told METRO on Tuesday.

"He injured her with a fruit knife and left home with the knife. As far as we know, Gao had no hatred of the two victims (at the restaurant) and the incident has no direct relation to KFC," he said.

The fatal stabbing took place at around 8 pm on Monday after Gao arrived at the KFC outlet near You'anmen Bridge, Fengtai district, and allegedly attacked two colleagues who were working in the kitchen. Officers from You'anmen police station arrived immediately and arrested the suspect.

One victim, surnamed Zhao, died shortly after being sent to a nearby hospital with serious stab wounds to his abdomen.

Another worker, surnamed Zhou, was treated for stab wounds to his legs and arms but his situation was described as stable.

The KFC outlet, which was closed shortly after the incident, reopened on Tuesday and it was business as usual when METRO visited after lunchtime. Customers were unaware of the tragedy and a waitresses declined to tell METRO more about Monday's incident.

A female worker from a nearby clothes shop told METRO she was aware of the stabbing after it happened on Monday evening.

In an announcement sent to METRO by KFC China on Tuesday, the company said it "felt deeply sorry for this tragedy".

Cheng Ping, from the company's publicity department, said the organization was cooperating with police in the investigation.

Cheng said KFC would release more information if it becomes available.