Jerusalem (CNN) Tension filled the small Jerusalem courtroom as a family sat meters away from the man who killed their son, waiting to hear the judge's verdict.

The defendant, Ben Deri, arrived accompanied by his family and girlfriend.

Deri was serving as an Israeli border policeman four years ago when clashes erupted near the West Bank village of Beitunya.

The date was May 15 -- when Palestinians mark the "Nakba" or Catastrophe, in memory of the more than 700,000 people who were either driven from, or fled, their homes during the Arab-Israeli war that accompanied the creation of the state of Israel in 1948.

CNN producer Kareem Khadder had a camera in hand and was filming at the precise moment Deri aimed and fired his rifle at Nadeem Nuwara. Nearby CCTV cameras captured the 17-year-old Palestinian walking unarmed before collapsing as a bullet entered his chest. A second Palestinian teenager was shot and killed by Israeli forces just over an hour later.

An Israeli military spokesman said a preliminary inquiry showed that live fire had not been used. Later investigations proved otherwise.

State prosecutors initially charged Deri with manslaughter, arguing that he knowingly used live ammunition. Under a plea deal, that charge was reduced to negligent homicide, with Deri admitting to an accidental use of live rounds.

The parents of late Palestinian teenager Nadeem Nuwarah, who was killed by Ben Deri.

To the end, Nuwara's family was convinced that Deri knew the type of ammunition he was using.

"Ben Deri's mentor described a responsible, accurate, committed and disciplined soldier," Siam Nuwara, Nadeem's father, told CNN. "I agree with the witness. Ben Deri is accurate and truly plans ahead. He knew very well what he was doing."

Judge Daniel Teperberg sentenced Deri to nine months in prison, and ordered him to pay Nuwara's family 50,000 Israeli shekels, or nearly $14,000. As the judge read the sentence, Deri's mother cried. Nuwara's family fumed with rage and called the decision a joke.

"Nadeem's case is the strongest," Siam told CNN after the trial. "We have all the evidence, strong evidence, but there is no justice in Israel."

Deri, flanked by his family and girlfriend, dodged journalists as he left the court just after the verdict. His lawyer, Zion Amir, said he was happy with the reduced charge and sentence, but insisted the case should never have gone to trial in the first place.

"We don't like the fact they are putting fighters on trial under circumstances like these," Amir told journalists. "We think [the soldiers and police officers] are carrying out their roles."

Video of the incident, including the material from CNN and captured by CCTV, helped build a picture of events. The court subpoenaed CNN's footage and ordered CNN producer Kareem Khadder to testify to defend the video's authenticity and recount the shooting.

"I saw a border police officer playing with his rifle, and later aiming at the protesters," Khadder recalled for the court.

"I waited until he fired, and waited further for a military personnel next to him to fire at the protesters, before panning the camera on to the protesters. During that time, I heard protesters in the distance shouting, 'Isaaf, Isaaf' -- they were calling for an ambulance."

A United Nations report about the incident found that Nuwara, and the other teen killed later, did not present a direct threat when they were shot.

The judge agreed with the report. His sentencing detailed how the rock-throwing had ceased by the time Deri shot Nuwara.

"Against procedures, and despite the fact there was no threat from the deceased [Nuwara] to the soldiers, the accused pointed his gun at the direction of the chest of the deceased and fired at him," the judgment read. It added that -- crucially -- Deri fired under the belief he was shooting a rubber bullet.

Palestinians said the killing and the subsequent verdict highlighted a double standard in the occupied West Bank, a place where they say Israeli soldiers and settlers act without real consequence.

"Such a conviction represents Israel's deliberate dehumanization of its Palestinian victims, primarily children, which is the outcome of decades of the military occupation that holds an entire nation under captivity, and employs an unremitting and lethal shoot-to-kill policy against Palestinians," Palestinian Liberation Organization Executive Committee Member Hanan Ashrawi said in a statement condemning the verdict.

Prosecutors said they were disappointed with the sentence, but added that it sent an important message to Israeli security forces.

"We thought the sentence should have been longer, but still the fact the court says someone will go to jail although he was there as a soldier has a powerful meaning," prosecutor Gula Cohen told CNN after the trial.