Donatella Rovera of Amnesty has been investigating Israel's weapons use
The BBC News Website looks at case studies of some of the weapons and tactics used in the recent Gaza conflict that human rights groups are concerned may have been violations of international law.
Interviews by Aleem Maqbool and Heather Sharp in Gaza City.
Human rights investigators have been trawling through the rubble in Gaza and gathering testimonies in an attempt to piece together a picture of the way both sides fought and the weapons they used.
International law demands that a distinction is made between combatants and non-combatants, and civilian casualties proportionate to the military gains from the attack in which they occurred.
But Amnesty International has concluded that some Israeli attacks "were directed at civilians or civilian buildings", while "others were disproportionate or indiscriminate".
As well as the way Israeli forces used white phosphorous in the conflict, which Amnesty has dubbed a war crime, the organisation has also raised concerns about other weapons and their use.
Amnesty has dubbed Israel's use of white phosphorus as a war crime
These range from the firing of high explosive artillery shells, which have a large margin of error, in populated areas, to concerns that Israeli forces were trigger-happy in their use of more precise weapons such as tank shells.
There has never been any doubt that Palestinian militants' use of rockets to target civilians in southern Israel was a violation of international humanitarian law.
Human rights investigators are also certain that the militant groups operated from civilian areas, although Amnesty and HRW are yet to publish detailed reports on the issue.
"The testimony and forensic evidence clearly shows Hamas was endangering the civilian population with its tactics," says Marc Garlasco, a senior researcher and military specialist with Human Rights Watch.
He says there were cases of Hamas firing from abandoned Palestinian homes.
"I myself saw Qassam rockets rise up from populated areas, likely fired from between homes," he adds.
Israel says the blame for civilian casualties lies with Hamas for using such tactics.
But Mr Garlasco - echoing the views of several other human rights groups - says this "in no way justifies what Israel did".
"The violations of one side do not allow the other side to fight in an illegal manner."
Israel has not yet responded to the specific allegations, but says it acts to minimise civilian casualties, and that its interpretation of international law is in line with that of other Western nations.
The Israeli military also says it is conducting internal investigations into some of the claims and individual cases, including regarding the use of white phosphorous, that rights groups have raised.
Flechette shells contain several thousand razor-sharp, nail-like metal darts, each about 4cm long.
Muhammad Abu Jarad still has a flechette lodged close to his spine
The shells explode in the air scattering the darts over the surrounding area - in a cone-shaped pattern 300m long and 90m wide, according to Human Rights Watch.
They are not banned under international law, but human rights groups say their indiscriminate nature makes them illegal if used in built-up civilian areas such as the densely populated Gaza Strip.
Although they were not widely used by Israeli forces in the Gaza conflict, Amnesty International has documented several incidents and says their use "contributed to unlawful killings" of Palestinian civilians.
The black darts can still be seen in the walls above the spot where Wafa Abu Jarad, aged 21 and three months pregnant, was fatally injured on 5 January 2009, outside their home on a residential street near Beit Hanoun in northern Gaza .
Her husband Muhammad, 24, said they had just had breakfast on the steps of their home, with their two-year-old son Khalil, and were walking among the lemon trees in their garden when they heard an explosion a few blocks away.
As they ran for cover in the house, Wafa with Khalil in her arms, there was another explosion above them. "All we could see were nails," said Muhammad, in reference to the flechettes.
"We were both thrown to the ground. She was bleeding from her head and chest," he said. "She fell unconscious immediately."
Young Khalil Abu Jarad has not yet been told his mother died in the attack
Flechettes hit Khalil in the legs, Muhammad in the leg and back, and flew through the open door hitting Muhammad's father in the shoulder, he said.
Wafa died in hospital three days later.
The clean white line of a flechette can be seen close to a vertebrae on an X-ray of Muhammad's back. He says he cannot sleep because of the pain, and sometimes finds his right side temporarily paralysed.
"The doctors are afraid to take it out, it is too close to the nerve - they are afraid I could be completely paralysed," he says, as Khalil clings to his leg and breaks briefly into a howl.
"What can I tell him when he cries 'Mummy, Mummy'?", he asks. "Where am I supposed to bring his Mum from?"
He tells the toddler Wafa is "travelling". "But yesterday he picked up a picture of her, and was saying 'Mummy, Mummy' and kissing it. He said she had been hurt in the explosion."
In similar cases, Amnesty International has documented the death of a 16-year-old boy, another woman and a paramedic, and numerous more injuries.
Israel has used flechette shells in Gaza for several years. In 2003 Israel 's High Court rejected a petition to ban their use, saying it considered the military's guidelines on their use to be adequate.
The Amnesty report says "tank rounds are precision munitions".
"The killing of so many civilians, many in their homes, indicates that these munitions were, at best, used in a reckless or indiscriminate manner," says the report.
Human Rights Watch military analysts say tank shells are so accurate they can be fired into a window from a distance of a mile (1.6km).
Haider al-Eiwa cannot understand why his house was hit
Both Amnesty and HRW investigators say there appeared to be a consistent pattern of Palestinian families being killed by Israeli tank shells fired into their homes, apparently as they approached windows or stepped on to balconies.
Haider al-Eiwa, 42, walks through the ruins of his family's top floor apartment in the eastern part of Gaza City .
Everything in the living room, dining room and kitchen has been reduced to a mangled, dusty mess.
A few weeks ago, he says, four of his children, aged between seven and 13, were playing by the kitchen window, looking out towards the Israeli border.
He says that, without warning, a tank shell crashed straight through the same window, killing his wife, and all four children.
"Of course they played near the windows, they are children," Haider says. "And the tanks were well over a kilometre away.
"They have destroyed my life. Why did they choose my house?" he says. "I am not Hamas, I don't belong to any group. They must have known there were children here."
Marc Garlasco of Human Rights Watch says: "I saw dozens upon dozens of homes damaged or destroyed by tank fire and our investigation noted numerous civilians killed in these cases."
"Though we don't know why they were killed, the Israeli army may have thought they were spotters for Hamas," says Mr Garlasco.
It seems that in some cases, Israeli forces were "looking through the vision system, firing at anything they saw moving", says Donatella Rovera of Amnesty International.
In another such case, cited by Amnesty, the house of Dr Izz al-Din Abu al-Eish was hit. A tank shell was fired into his daughters' bedroom. Three of his daughters and his niece were killed.
Unmanned drones (one visible, top right) were used extensively by Israel over Gaza
Marc Garlasco of HRW says there is concern about the number of Palestinian civilians killed by missiles fired from unmanned Israeli aircraft, or drones, particularly because these can be precisely targeted and guided by an operator using imaging "like a TV camera" as they home in on their target.
In several cases, children were killed as they played on roofs, despite the fact that the operator should have been able to determine they were civilians and steer the missile away, he says.
"It appears there was this wider policy to kill anyone on a roof," he said.
Furthermore, investigators found that many of the missiles used in such strikes contained tiny, sharp-edged cubes of purpose-made shrapnel, which are scattered as the missile explodes.
Mr Garlasco says these were designed as anti-tank weapons, but are often used by Israel for targeted killings, as they "do they job well" - the blast is confined to a small radius, the missiles are relatively light and can be mounted on unmanned drones.
Mahmoud al-Habbash says he cannot remember the blast that "sucked" him
Mahmoud al-Habbash, 15, shows us the spot on a rooftop where his cousins were killed by a guided missile. According to HRW, the missile contained such cube-shaped shrapnel.
"We were feeding the chickens and playing," he says. "We did it every day and did not think we had any reason to be afraid."
"I looked to the sky and I saw a flame coming towards us and I shouted and ran. It was strange, I was suddenly sucked back forcefully, but I don't even remember hearing the blast," says Mahmoud.
"Shada, who was 12 and Isra who was 10 were killed. Jamila lost both legs, she is 14. Muhammad who is 16 lost one leg. Muhammad says when the explosion happened, it looked like there was a huge cloud of flies around us."
Qusai al-Habbash, 48, a science teacher and the father of the two girls who died, says the area had been calm and that families along the street had been going about their business as normal.
"Still, I thought of warning my children not to go outside, because of what was happening in other areas," he says. "But then I told myself that the Israeli weapons were very sophisticated. They can easily see who is a child and who is a militant. But they killed my children anyway."
Amnesty has listed many cases in which civilians were killed in this manner, including eight secondary school students who were waiting for the school bus to take them home