A veteran U.N. war crimes investigator acknowledged his probe of possible war crimes by Israel and Hamas — which included interviewing dozens of victims and poring through the files of human rights groups — is unlikely to lead to prosecutions.

Israel has refused to cooperate, depriving his team access to military sources and victims of Hamas rockets. And Hamas security often accompanied his team during their five-day trip to Gaza last week, raising questions about the ability of witnesses to freely describe the militant group's actions.

But the chief barrier remains the lack of a court with clear jurisdiction to hear any resulting cases stemming from the investigation into Israel's three-week offensive in Gaza which ended in January and was designed to stop years of Hamas rocket fire into southern Israel.

"From a practical political point of view, I wish I could be optimistic," Judge Richard Goldstone said, citing the legal and political barriers to war crimes trials.

Still, Goldstone hopes his group's report — due in September — will spur action by other U.N. bodies and foreign governments.

Goldstone, a South African judge who prosecuted war crimes in the former Yugoslavia and Rwanda, refused to comment on the investigation's content. But AP interviews with more than a dozen Gazans who spoke to the team reveal a wide-ranging investigation into the war's most prominent allegations.

In Gaza, Goldstone's 15-member team met with Hamas and U.N. officials, collected reports from Palestinian human rights groups and interviewed dozens of survivors.

Among them was a Bedouin man who told the investigators how he watched Israeli soldiers shoot his mother and sister dead as they fled their home waving white flags. But he, too, doubted he would see justice.

"The committee was just like all the others who have come," said 46-year-old Majed Hajjaj. "There are lots of reports written, but they're nothing more than ink on paper."

The U.N. team also stepped through the shrapnel-peppered doorway of a mosque where an Israeli missile strike killed 16 people, witnesses said. During the war, Israel accused Hamas of hiding weapons in mosques. Witnesses said no weapons or militants were present.

They inspected holes in the street near a U.N. school where Israeli artillery killed 42 people, and visited the charred skeleton of a hospital torched by Israeli shells. In both cases, the army said militants had fired from nearby, and witnesses said some had been near the school.

And they visited the Samouni family, whose members say they took refuge on soldiers' orders in a house that was then shelled, killing 21 people.

Israel denies the account, but says the house may have been hit in crossfire with militants.

Israel launched the offensive to stop eight years of Hamas rocket attacks. Palestinian human rights groups say more than 1,400 Gazans were killed, most of them civilians. Israel says around 1,100 Gazans were killed and that most were militants, but — unlike the Palestinian researchers — did not publish the names of the dead. Thirteen Israelis were also killed, three of them civilians.

Human rights groups called for war crimes investigations soon after the war's end, accusing Israel of disproportionate force and failing to protect civilians. Some groups and the Israeli army said Hamas fought from civilian areas and used human shields — all of which can be war crimes.

Israel's refusal to cooperate meant that Goldstone — a Jew with close ties to the Jewish state — had to enter Gaza via Egypt.

Speaking to a parliamentary committee on Tuesday, Israeli Foreign Minister Avigdor Lieberman said Israel had made a "clear decision" not to cooperate, alleging anti-Israeli bias by the probe's sponsor, the U.N. Human Rights Council.

The council has a record of criticizing Israel's treatment of the Palestinians.

Lieberman also mentioned that Goldstone team member Christine Chinkin, a law professor at the London School of Economics, signed an editorial published in the Sunday Times in January calling the Israeli offensive a war crime. This showed she could not be objective in her findings, Lieberman said. More than 20 scholars and jurists signed the letter.

Israeli Defense Minister Ehud Barak said investigators could not reach an "unbiased conclusion" since they couldn't question those who fired rockets at Israel.

When asked if the team met with Hamas fighters, team member Hina Jilani declined to comment, but said Hamas had been "very cooperative."

A Hamas official, Ahmed Yousef, said he hoped the group's report would be "like ammunition in the hands of the people who are willing to sue Israeli war criminals."

Some survivors said the team pressed them on Israel's assertion that it made warning phone calls before airstrikes and whether militants fought or fired rockets from their neighborhoods.

"They asked for all the details. Were there rockets fired from the area, why did they target this area specifically, stuff like that," said Ziad Deeb, 22, who told the team how he lost 11 relatives and both his legs when an artillery shell exploded on his doorstep.

Alex Whiting, a professor at Harvard law school, called Goldstone "supremely qualified" for such an investigation, but said such cases are hard to investigate, especially without military records. He also said there are few mechanisms for prosecution if crimes are uncovered.

But even without prosecution, Whiting said, inquiries can spur countries to investigate themselves or affect future wartime conduct.

"Many times, the immediate result is a disappointment for the victims and survivors, but the hope is for the future," he said.