Human Rights Watch and other groups allege that Israel's tactics for achieving a military advantage in Gaza led to disproportionate death and suffering of a civilian population that was denied medical care, refuge and electricity, especially in the urban warfare in and around Gaza City.

"Gaza became a kind of free fire zone for the Israelis," said Fred Abrahams, senior emergencies researcher for Human Rights Watch.

Abu Freeh said that as the Israelis moved in, neighbors said, the Israeli soldiers took over Abu Freeh's house, moved the seven people living there into one room and began interrogating the adults. The questioners were angry because one of their soldiers had been killed nearby in the early hours of the ground offensive, and they wanted to know what traps Hamas had set for the Israeli forces.

"Where are the tunnels?" Abu Freeh said the soldiers asked in Arabic. "I will kill you if you don't tell me."

Israeli tanks and bulldozers soon took up hilltop positions around Abu Freeh's home, and Khaled Abed Rabbo's five-story house in the valley below was one of those in the line of fire.

More than 70 members of his family crowded into one apartment for days. On Jan. 7, Abed Rabbo said, the shelling intensified, and they heard an Israeli solider calling for people to come out of their homes.

Abed Rabbo said he gathered his wife, their three daughters and his mother, Souad. Souad Abed Rabbo said that she tied a white robe around a mop handle and two of her granddaughters waved white headscarves as they walked outside.

When they opened the door, they saw an Israeli tank parked in their garden about 10 yards away.

"We were waiting for them to give us an order," Khaled said last week as he stood in the ruins of his home. "Then one came out of the tank and started to shoot."

Souad Abed Rabbo said she was shot as she pushed her son back inside and her granddaughters fell on the stairs. When the shooting was over, she said, 2-year-old Amal and 7-year-old Souad were dead.

The allegation is one of at least five such white flag incidents that human rights investigators are looking into across the Gaza Strip. It's part of a growing pattern of alleged abuses that have raised concerns that some Israeli soldiers may have committed war crimes during their 22-day military campaign in Gaza.

"The evidence we've gathered in two of the cases so far is exceedingly strong," said Fred Abrahams, a senior researcher with Human Rights Watch working in the Gaza Strip. "All the research so far suggests they shot civilians that were leaving their homes with white flags."

Along with the white flag incidents, Human Rights Watch is calling for an international investigation into widespread charges that Israel prevented medical teams from helping wounded Palestinians trapped in their homes and needlessly demolished hundreds of houses, including dozens in Ezbt Abed Rabbo.

"This was not a rogue unit," said Abrahams. "The needless civilian deaths resulted from concrete decisions made by the military."

Samieh al Sheik, an ambulance driver who lived in an adjacent home, heard the shouting. Without thinking about what could be waiting outside, Sheik said he ran to his ambulance, turned on the emergency lights and drove toward the screams.

As he turned the corner and headed for Abed Rabbo's home, Sheik said he came face-to-face with the Israeli tank unit. The soldiers ordered him to get out of the ambulance and told him to walk straight out of the neighborhood.

"I didn't see what happened to the family that day because I couldn't reach them," said Sheik, who returned to find the ambulance crushed under a demolished building.

Faced with his dying children, Abed Rabbo gathered up the wounded and sought to escape, even if the Israelis opened fire.

With Israeli soldiers shooting at the ground near their feet, Abed Rabbo said, the family walked more than a mile to the main road, where they finally found help. His surviving 4-year-old daughter, Samer, was one of the few to be allowed out of Gaza to receive special medical care in Brussels.

Halima Badwan was less fortunate. As Abed Rabbo rushed his surviving daughter to the hospital, she lay dying in a house nearby.