Xu Chunhe, 45, was shot when he tried to get through the security checkpoint at a railway station in Northeast China's Heilongjiang proince on May 2. [Photo/IC]

BEIJING -- A procuratorate's investigation into a fatal shooting at a railway station in northeast China has confirmed the legitimacy of the police act following questions from the public.

When police officer Li Lebin shot Xu Chunhe on May 2 at Qing'an County Railway Station in Heilongjiang Province he was acting within the law, according to a statement issued by the railway transport procuratorate of Harbin, the provincial capital.

His use of the firearm conformed with regulations, as well as his responsibilities as a police officer and protector of the peace, the procuratorate's investigation concluded.

The procuratorate's findings are consistent with a previous statement released by the Harbin Railway Police that said the gun had been discharged in the line of duty and Li had not broken any laws or protocols.

Xu, 45, was traveling with Quan Yushun, his 81-year-old mother, and his three children, when he attacked Li and continued to assault the police officer despite multiple warnings, resulting in the fatal shooting, the statement said.

Xu was confirmed dead at the scene by paramedics who arrived at the scene 25 minutes later.

Surveillance footage of the incident was made public on May 14, but despite this, doubts remained over the authenticity of the tape, the legality of Li using the gun and the cause of the altercation.

There was also speculation that the local government had paid "hush money" to Xu's family to silence them.

It has been confirmed that the surveillance footage was original and not edited. The clip that was disseminated to the public by media outlets was taken from the original footage, said Gao Lei, a forensic examiner with the digital forensic center under the Beijing Network Industry Association.

A witness said, on condition of anonymity, that the online brouhaha questioning the authenticity of the video made him very angry.

The tape shows Xu, his mother and three children arriving at the railway station on the morning of May 2, and Xu buying tickets to Dalian, a city in neighboring Liaoning Province. The whole family then went to a nearby restaurant for lunch, before returning to the station and sitting in a waiting room.

At around 12 p.m., Xu can be seen blocking the security check passage with a trolley and closing one of the doors to the waiting room. A security guard called for police assistance and Li responded. Despite various warnings and attempts at persuasion, Xu refused to stop blocking the security passage. When Li opened another door to let passengers in, Xu threw a bottle of water at him.

A struggle followed, during which Xu moved to pull something from his waist. Alerted, Li drew his gun but did not raise it. Confirming that there was no threat, he replaced the gun in its holster.

Observing that the situation was growing more volatile, Li returned to his office to fetch a baton, closely followed by Xu.

As Li attempted to restrain Xu, he met violent resistance. Having tried to grab the baton, Xu pushed his elderly mother into the officer. He then tried to push his daughter toward the officer, knocking the little girl to the ground.

At around 12:06 p.m., officer Li discharged his firearm.