SAO PAULO, Brazil (AP) _ An American handwriting expert said he is certain Nazi death camp doctor Josef Mengele, who police believe may have died near Sao Paulo, wrote some documents discovered in Brazil.

''We have made a definite identification of the handwriting of Josef Mengele in documents found in Brazil,'' Dr. David Crown, who was hired by the U.S. Justice Department, said Friday night. ''There is not a shadow of a doubt as to the authenticity of the handwriting in the documents.''

The federal police chief in Sao Paulo, Romeu Tuma, said the handwriting identification ''shows that the body unearthed at Embu and which lived in four different houses in Brazil wrote those documents. That means that our preliminary conclusion is that the body belongs to Josef Mengele.''

Crown is among experts attempting to identify the remains and belongings of a man Brazilian police say they believe is Mengele. Police, acting on a tip from West Germany, dug up the man's body June 6 in the town of Embu, 17 miles from Sao Paulo.

Mengele, known as the ''Angel of Death,'' is accused of directing the killings of some 400,000 Jews and others and conducting heinous human experiments at Auschwitz concentration camp in Poland during World War II.

Crown compared documents found in Brazil with classified war documents sent by the United States, including Mengele's handwritten application to enter the Nazi elite SS organization. Federal police said the documents found in Brazil were letters and notes discovered at a house in which the man believed to be Mengele lived.

''We are staking our reputations on this,'' Crown said of he and other experts who examined the documents.

Tuma has said investigations inidicated the man thought to be Mengele lived in Brazil for at least 15 years and drowned in 1979.

The police chief said fingerprint tests on the notes have not revealed any clues.

Tuma said anthropologists examining the bones concluded ''the age of the skeleton is in the same age bracket as Mengele.'' The Nazi doctor would have been 68 in 1979.

Police said they had contacted West German police to obtain possible proof of identification from Mengele's son, Rolf, who claims his father died in Brazil in 1979. Dr. Ramon Manubens, a member of the forensic team, said he found ''peculiar characteristics'' on the remains and medical records from the son ''can be very important to the investigation.''

The West German magazine Bunte said it had received hundreds of photographs, letters and documents from Rolf Mengele purportedly tracing his father's escape route from Germany after the war. Chief editor Norbert Sakowski said they were provided free of charge, and would be published after verification by historians.

The body was buried under the name of Wolfgang Gerhard, a soldier in the Nazi army who is alleged to have protected Mengele in Brazil. Police say he was reported to have given his Brazilian identification card to Mengele when he left Brazil in 1975.

Gerhard died in Austria in 1978, and West German Vice Consul Seep Woelker told reporters in Sao Paulo on Friday that his government has asked the Austrians to exhume Gerhard's body.

Adolf Gerhard, Gerhard's son, said in Graz, Austria, that the family will release a statement telling what it knows about his father's dealings with Mengele only after investigations in Brazil are complete.

''I was dismayed when I heard that Gerhard should have passed his identity to such a man,'' said Stefan Wech, head of an advertising agency in Graz and Gerhard's former boss.

Wech described Gerhard as more than six feet tall. Experts in Brazil have said the remains are of a man about 5 feet eight inches tall. Mengele was 5 feet 71/2 inches tall, according to medical records.

Wech praised the elder Gerhard as a conscientious and competent advertising salesman who ''made no bones about being a 150 percent Nazi'' but would not discuss details of his life in South America.

Wech said Gerhard had problems with his personal documents and so apparently stayed in West Germany for a while before returning to Austria.

The head of the U.S. Justice Department's Nazi-hunting unit, Neil Sher, said in Washington that the department had taken no position on whether the remains are Mengele's.