GRAPHIC CONTENT WARNING:

Jason Harrison shooting
The final moments of Jason Harrison's life were captured on the police officer's video camera.

A graphic video of the moment a mentally ill man was shot dead by police on his own doorstep has been released.

Jason Harrison, 38, was shot three times during a confrontation with police as he stepped out of his front door in Dallas, Texas, in June 2014.

His mother, Shirley Harrison had called police to the family home asking for assistance to have Jason admitted into hospital. She explained to officers John Rogers and Andrew Hutchins that her son was a "bipolar schizo."

The officers arrived to find Mr Harrison holding a screwdriver, however when they told him to drop it, the situation was aggravated and following a heated exchange, shots were fired and he was dead.

Explaining their actions, the officers claim they feared for their lives after Jason lunged at them and fired in self-defence. Jason's family argue that he was not a violent person and was simply agitated by the yelling and the volatile situation.

Footage from one of the officer's body cameras was handed over to the family as part of a lawsuit claiming the police department was responsible for Mr Harrison's wrongful death.

Mr Harrison's brother Sean has questioned why the officers did not use a Taser or pepper spray and said that the incident demonstrates that the police need to be trained in how to deal with people suffering from mental health problems.

He told the Dallas Morning News: "This is a perfect video for the Dallas Police Department to use in training as an example of what not to do. You don't yell at them - that only agitates them."

The shooting is the latest in a series of incidents that have led to escalating tensions between the police and the black community.

Similar shootings in New York, Los Angeles, Wisconsin, Washington and the killing of the unarmed black teenager Michael Brown in Ferguson, Missouri two months earlier, have sparked a nationwide debate about the use of deadly force by police.

A number of cities have begun using body cameras for police officers to provide images in cases where actions are challenged. The latest shooting was the first in Dallas to be captured on a body camera. Officer Hutchins had bought the camera himself as his city-issued one was not working.

The district attorney in Dallas has been formally assessing the family's lawsuit against the city's police department and the case is expected to be presented before a grand jury.