KRAVICA, Bosnia-Herzegovina (AP) _ Investigators who picked through skeletons and shreds of clothing for evidence of war crimes have ended excavations of eastern Bosnia's mass graves until next year.

Four hundred to 500 bodies have been recovered. But the approaching winter snow will conceal at least until spring answers to a broader question: the exact fate of the most of the 7,000 Muslims missing from Srebrenica.

Investigators dug up mass graves this year searching for evidence to help build cases against suspected war criminals. But human rights officials says that excavation of all mass grave sites is necessary for Bosnians to begin looking to the future.

Mass graves dot the Bosnian countryside after 3 1/2 years of war, but most attention has been focused here in the east. In July 1995, Bosnian Serbs took the Srebrenica enclave and tens of thousands of Muslims fled or surrendered.

Among the captured, men were separated out and most disappeared. Witnesses reported mass executions.

Many died in attacks in places like Kravica, nine miles northwest of Srebrenica. Hundreds of bodies have lain exposed for 14 months on the ground where they fell.

With no proof, relatives and survivors cling to rumors that their men are alive in Serb prisons or hiding in the mountains.

``Yes, I have heard that, and I hope that there is still some hope that my grandson will be found alive,'' said Hatidza Ahmetovic, whose 17-year-old grandson was last seen at the site of a Serb ambush a day's walk from Srebrenica.

Investigators bristle at the idea that anybody is holding out serious hope that their friends or family survived.

The graves that have been dug up have provided evidence of execution: many of the bodies removed from Nova Kasaba had bound hands, and victims exhumed from Lazete were blindfolded.

Alexander Ivanko, a U.N. spokesman in Sarajevo, said Wednesday that investigators would continue trying to identify remains they had unearthed, and would resume excavations next year.

The exact number of remains unearthed was difficult to determine because they were in bad shape, Ivanko said.

The U.N. expert on missing people in Bosnia, Manfred Novak, said there were more than 10 mass grave sites. There are an unknown number of other sites like Kravica where bodies were left strewn on the ground.

Investigating every site linked to Srebrenica is essential ``if we want to know what happened, if we want to tell the families the truth,'' Novak said.

One problem is that investigators from the United Nations and Muslim-led government willing to take on the broader task say they lack the NATO military protection afforded tribunal investigators.

Bodies now are being removed from above Kravica as part of an exchange between the Muslim-led government and Bosnian Serb authorities, not as part of the international tribunal's war crimes investigation.

Serbs here well know of the bodies at Kravica, but like most Serbs in Bosnia, accept no blame. They alternately claim the Muslims killed each other or were soldiers killed in combat. In any case, in the words of a former Serb soldier who refused to be identified, ``They deserved worse.''

Despite those assertions, the remains of bodies littering the forest floor are clad in civilian clothes: blue jeans, work pants, rubber boots and leather dress shoes _ no military uniforms.

Ammunition pouches and unexploded rocket-propelled grenades are scattered, but no guns have been recovered.

Muslim men who say they survived an ambush in the hills above Kravica claim they were mostly civilians trying to reach Muslim-held land after Srebrenica fell.

They have no idea how many people died there, or how many might have surrendered as the column of up to 15,000 was splintered by Serb attacks.

Providing the answers is more than a humanitarian question, said Novak.

``If this whole question of the disappearances is not solved to the satisfaction of the families and of the politicians, I think it will be a major obstacle to peace,'' he said.