"It is the opinion of the (Fresno County) District Attorney's Office that the shooting death of (Dylan) Noble did not involve any criminal conduct by Fresno Police Department Officer Raymond Camacho or Officer Robert Chavez," District Attorney Lisa Smittcamp's statement said.
Noble, 19, was shot four times in June by the Fresno officers, twice as he approached them and twice more while he was on the ground.
CNN was not able to contact Noble's family on Friday.
Several months ago, Stuart Chandler, an attorney for Veronica Noble, Dylan's mother, said: "We're shocked and appalled that the city of Fresno would continue to defend the actions of its officers. Clearly the only appropriate response is to accept responsibility and commit to changing practices of the police department."
Speaking in July, Fresno Police Chief Jerry Dyer said the officers originally responded to a report of a man carrying a rifle while walking down the street.
The two officers were in the same car and stopped at a red light when a black pickup truck made a turn in front of them with screeching tires and appeared to speed away. They followed the truck to a gas station where officers got out of the patrol car with weapons drawn.
Over a period of about two minutes, the officers command Noble to put both hands out of the truck window and, after he gets out of his vehicle, to lie on the ground.
Noble walks toward the officers with his right hand behind his back, despite orders to stop and get on the ground. At one point, Nobel says, "I (expletive) hate my life."
An officer fires a handgun twice. Noble goes down and rolls onto his back. When Nobel continues to move, the officer fires again. Noble squirms while he is told to not to move his hands. About 14 seconds later, another officer fires a shotgun once.
Noble was unarmed. He had in his possession what Dyer described as a piece of clear plastic, 4 inches by 4 inches, that contained moldable clay.
After the shooting, Dylan's Noble's family questioned the officers' actions. Dylan Noble's father, Darren, was "extremely disappointed at the way the police handled this shooting and he's relying on outside agencies for providing him with answers and justice," said Warren Paboojian, a lawyer for Darren Noble.
"You don't point (a weapon) at an individual for a traffic stop," Paboojian said.
"The District Attorney's Office's investigation of this incident consisted of several hundred hours of investigation and review, and included numerous conferences among the most senior and experienced prosecutors and investigators in the District Attorney's Office," the news release said.