A mentally ill gunman shot and killed three people, including a child, at a Target in Texas on Monday – before stealing two cars during a dramatic getaway, cops said.

The 32-year-old, who hasn’t been identified publicly, ended up being arrested hours later after police used a Taser to detain him, according to cops. 

The deadly saga unfolded when the alleged perp, who authorities said had “a mental health history,” stormed the parking lot of the Target just north of Austin at around 2:15 p.m.

Three people were killed and a fourth victim, who suffered unrelated injuries, was treated at the scene, police said.

The gunman fled the scene in one of the slain victims’ cars.

He proceeded to crash that car and then hijacked another one from a Volkswagen dealership.

The perp was eventually captured some 20 miles away in the city’s south, according to police.  

“This is a very sad day for Austin. It’s a very sad day for us all and my condolences go out to the families,” Austin Police Chief Lisa Davis said.

One of the three dead was a child, cops said, without giving any other details about the victims, including the child’s age.

Police are also still working to determine a motive.

Target, meanwhile, said they were “devastated” by the tragedy and would be providing grief counseling to their team.

“Our hearts are with the families and loved ones of those who lost their lives, our team in Austin and all those impacted by this tragedy,” the outlet said in a statement.

With Post wires