The son of Dr. Josef Mengele, the infamous Nazi war criminal whose suspected death in Brazil six years ago is being scrutinized by experts from four countries, plans to break his family's long silence in the case in the next 48 hours, according to sources close to the family.

An associate of Rolf Mengele, who runs a law practice in Freiburg, said the son is in seclusion but plans to issue a statement by Wednesday that may shed light on the family's secret connections with the Auschwitz concentration camp doctor during his years as a fugitive in South America.

Asked why there was a delay in making public the family views, the associate said, "Wait until you hear or read the statement. You will see what the point is."

A secretary for a nephew of Mengele who manages the family's prosperous farm machinery business in Guenzburg, confirmed that a declaration is being prepared. She said her employer was out of town and could not be reached for comment.

Hans Eberhard Klein, the Frankfurt prosecutor in charge of the Mengele case since 1974, said he had no prior knowledge of the statement's contents. He denied that Rolf Mengele was under investigation for aiding and abetting a criminal fugitive.

During the long hunt for Mengele, his family adamantly has refused to cooperate with police or divulge any information that would betray his possible whereabouts.

Klein admitted that his office has received no help from the Mengele family in tracking the Nazi doctor, who until recently was believed to be hiding in Paraguay. But he emphasized that under West German laws that guarantee privacy, Mengele's relatives could not be forced to testify about him.

On May 31, West German police, acting on a tip from a university professor who overheard a man boasting about supplying funds to Mengele, raided the home of Hans Sedlmeier, a former senior employe of the family firm in Guenzburg.

There they discovered a cache of letters, some possibly written by Mengele himself, that were traced to an Austrian couple living near Sao Paulo, Brazil. The couple, Wolfram and Liselotte Bossert, have said that they provided lodging for Mengele during the 1970s.

After the Bosserts claimed Mengele died in a swimming accident in 1979 and was buried under the name of Wolfgang Gerhard, police exhumed the body last Thursday and are now conducting forensic tests to identify the body. If alive, Mengele would be 74.

Other revelations by the Bosserts have indicated that the Mengele family maintained sporadic contacts with the Nazi fugitive and may have furnished money to subsidize his life on the run. Sedlmeier, who is being investigated by Klein for possible obstruction of justice, reportedly served as a key contact linking Mengele and his family.

The Bosserts told police that Sedlmeier handled mail between the family and Mengele's acquaintances in Sao Paulo, working through a middleman called "Herr Schweigart" in Augsburg.

Names in the letters were coded, with Mengele known as "Beppo," Wolfram Bossert as "Mus" and Sedlmeier as "Messerle," or Little Knife, an apparent reference to knives bearing the Mengele family name he brought to Sao Paulo once as a gift.