Joe Stork, Human Rights Watch's Middle East director, said in a statement: "Israeli soldiers did not make sure they were aiming at a military target before firing, and there is evidence suggesting they actually targeted the journalists."
However, the Israeli military has strongly denied that the camera crew was deliberately targeted.
"The cameraman was in a combat zone at a time when our forces were coming under fire," a military spokeswoman said.
"Allegations that the Israeli army targeted the journalist are completely baseless. The IDF [Israel Defence Force] makes every effort to avoid casualties among those not implicated in acts of violence."
She said that the results of the inquiry would be handed to the military advocate general.
Shana's final piece of footage showed an Israeli tank firing a shell just before the camera went black. Other journalists who arrived at the scene shortly after the shelling also said they came under tank fire.
"The Reuters truck was clearly marked 'TV' and 'Press' and drove by the tank twice, so it's hard to believe the Israeli tank crew didn't see the pickup contained only journalists," Stork said.
|The vehicle the cameraman was travelling in|
was clearly marked [AFP]
Shana's protective vest, which also had a blue-on-white "Press" marking, was ripped off by the attack, which medical examination showed had thrust several 38-mm metal darts, known as flechettes, through his neck severing his spine.
Two more Palestinian teenagers wounded in the attack died of their injuries on Sunday raising the death toll from the incident to six people, according to medics.
About 20 Palestinians had died in clashes with the Israeli military on the day of the incident, many of them civilians, after fighters had earlier killed three Israeli soldiers.
Several dozen journalists marched through the West Bank city of Ramallah on Sunday, led by a group carrying a stretcher with a camera and a tripod to protest against Shana's killing.
They carried a banner reading: "The occupiers are responsible for the blood of our colleague."
Meanwhile, at least two Palestinians were killed in an air raid in southern Gaza, bringing the death toll for the last two days to nine people.
The Israeli military confirmed the attacks saying it targeted a group of armed men.