In the US state of Arizona, a police officer killed a 61-year-old suspected shoplifter in a wheelchair with nine shots in the back.

Tucson City Police Chief Chris Magnus posted a video of the incident Tuesday night and said the officer would be fired.

"His fatal use of force during this incident is a clear violation of the rules of our service," Magnus said to journalists.

The police officer was not on duty on the evening of the crime, but worked as a security guard for a supermarket of the Walmart chain.

A supermarket employee informed him that a man in a powered wheelchair had just stolen a toolbox.

When the 61-year-old was asked to show a receipt for the purchase, he pulled out a knife, called “Here is your receipt!” And drove away.

Nine bullets in the back

The security guard asked the suspected shoplifter several times to stop and drop the knife.

This ignored the requests according to the information and went to a nearby hardware store.

The police officer then shot the wheelchair user with nine bullets in the back.

The policeman's attorney, Michael Storie, told the New York Times that his client had tried to bring the situation under control.

However, the behavior of the alleged shoplifter left him "no other choice" than to use his weapon.

In the USA, fatal police operations repeatedly cause outrage, in many cases violence against members of minorities.