A US man has been arrested following a shootout with police, after he allegedly shot his grandmother and killed her husband.

Patrick Canada, 25, has since been charged with malice murder and aggravated assault after he allegedly shot and injured Pamela Lynn Henn, 64.

The accused also gunned down and allegedly killed his step-grandfather, Douglas Keith Henn in their home.

Pamela and Douglas Henn were allegedly shot by Patrick Canada. Photo: Facebook. More

A 911 call recorded Canada arguing with the couple moments before the fatal shooting.

Canada lived with his grandmother in their home.

Police responded to an emergency call about a domestic dispute at the Lake Hollow Court home in Douglasville,

Georgia, about 9.15pm local time Sunday.

When police arrived they found Canada armed with a gun, which he then allegedly used to shoot at an officer,

according to AJC.com.

Police said during the shootout an officer’s gun malfunctioned and he retreated to his patrol car to get his rifle.

The officer saw Pamela Henn attempting to flee from her grandson, suffering multiple gunshot wounds.

Ms Henn was rushed to hospital and survived.

Her condition is unknown.

Douglas Henn’s body was found in a pool of blood with multiple gunshot wounds at the home.

Canada attempted to flee however he was confronted by a police officer outside the home and arrested.

The motive is unclear, however police suspect Canada was arguing with Mr Henn before the shooting.

Canada is being held in custody.

His mugshot was released to the public showing him covered in blood splatter.