The youngest victim of the gunman who slaughtered four people in Orange, California was a 9-year-old boy who died in his mother’s arms, officials revealed Thursday — and the shooter knew them all through the real estate business where they all worked.

“They were all known to each other,” county District Attorney Todd Spitzer told reporters, revealing that the shooting was not random and identifying the lone shooter at an afternoon press conference as Aminadab Gaxiola Gonzalez.

Gonzalez, 44, of Fullerton, had “issues” with his co-workers at the location, a mobile home real estate office suite, Spitzer said.

“It appears a little boy died in his mother’s arms as she tried to save him,” the visibly angry prosecutor told reporters.

“He will suffer and face the consequences,” he added of Gonzalez, calling the “horrific rampage” death penalty-eligible.

“Our hearts today go out to the victims. We pray for one of the victims who is still in the hospital who underwent emergency procedures,” he added, an apparent reference to the boy’s mother.

Gonzalez also remains in the hospital with critical injuries after suffering a “police-involved shooting” during his arrest.

Dramatic video shows the alleged gunman being dragged from the property by police.

Officials said at the press conference that shots were still being fired when officers arrived at 5:30 p.m. local time Wednesday at the scene, a two-story office building 30 miles south of Los Angeles.

Gonzalez used bicycle-type locks to secure the gates on the north and south end of the complex’s courtyard, temporarily barring police from entering as the shots were being fired, officials said.

The suspect was shot through one of the gates, which were then forced open, they said.

Inside the courtyard, officers found the 9-year-old boy who died, being cradled by a woman who was also injured.

The three other victims — two women and a man — were found inside the office complex.

Officials said the shootings were centered on a real estate and contracting business called Unified Homes.

They recovered at the scene a semi-automatic handgun and a backpack holding pepper spray, handcuffs and ammo that are believed to belong to the suspect, officials said.

The victims, whose identities have not been released, all shared personal and business connections to Gonzalez, officials said. The child is the son of one of the employees of Unified Homes.

Per: NYP