No fewer than three people, including a child, died at a Target Store in Austin, Texas, on Monday after a gunman opened fire on innocent residents before stealing multiple vehicles, according to local police.

The attack, being the third in two weeks, marked an uptick in gun violence incidents involving mental health patients.

A 32-year-old White man, confirmed as having a mental illness record, fired live rounds at Target’s parking lot, killing a child and the driver of one of the vehicles he hijacked before fleeing the scene.

After crashing the first vehicle, he stole another car at a car dealership. Local police subdued him with a taser to take him into custody when he got out of the car in South Austin.

Two people, including a child, were declared dead at the shooting scene, while a hospital near the Target store pronounced the third person dead, and the fourth sustained minor injuries.

Police chief Lisa Davis said the gunman, whose name was withheld, had a history of mental illness and had been previously placed on emergency holds, usually prescribed for patients deemed a risk to themselves.

“This is a very sad day for Austin, a very sad day for us all,” Ms Davis said.

Austin’s mayor, Kirk Watson, described the attack as “a sickening, cowardly act of gun violence.”

“This is a devastating situation, and my heart is with the victims and their families,” Mr Watson wrote on social media.