David Truong, who has been charged with passing confidenital documents to the Vietnamese Communist government, may not have known that the documents were secret, according to a statement read yesterday before the 4th U.S. Circuit Court of Appeals.

Ronald Humphrey, the United States Information Agency employe who is accused of stealing the cables to give to Truong, said in a statement read in court that the names addresses, and classifications of the documents were removed before Truong received the documents.

Humphrey said in the sections of the hitherto sealed statement read yesterday, that he would photocopy the document, cut off the names, addresses and classifications, and tape the remaining parts of the photocopy to other pieces of paper.

"The reason I cut off the classifications and addresses," Humphrey said in his statement, "was in an attempt to disguise the sensitive nature of the documents."

Humphrey's statement was read as attorneys for Truong, the son of a one time South Vietnamese peace candidate, asked the court to reduce his $250,000 bond so he could get out of the Alexandria jail to prepare for his defense.

Humphrey's statement has been frequently cited by prosecutors as a major element in the government's case. Alluding to it, Marvin Miller, one of Truong's attorneys, said "the only evidence they (the government) have presented so far is exculpatory and clearly exonerates our client." Outside the courtroom , Miller said, "If there's no client and no knowledge, how can he be guilty?"

Assistant United States Attorney Robert McDermott told the court yesterday, however, that "The Strength of the government's case is not dependent on the statement." There is "ample evidence," based on wiretaps and electronic survellance, he said, as well as "testimony in confidence of an informer who was personally present at the time of those transactions." He did not specify which transactions the informer says he witnessed.

McDermott also said that the government intends to try the cases of Truong and Humphrey together and may not introduce Humphrey's statement as evidence.

Judges Clement F. Haynsworth Jr., Donald Russell and H Emory Widener listened during a hearing here yesterday as Truong's attorneys asserted that he has no money and his bond is excessive. His sister and brother-in-law have agreed to put up their California home, in which they have $58,000 equity, as security, but that appears to be the limit of his financial resources, the judges were told.

In addition to raising questions about the strength of the government's evidence, attorneys argued yesterday that cable traffic cited in Truong's indictment was not relevant to the national defense.

They submitted affidavits from former attorney general Ramsey Clark, Rep. Robert Drinan, MIT professor Noam Chomsky and George Wald, among others, testifying to Truong's good character.

The government replied in one of its briefs, however, that "it is no surprise considering the nature of the offense, that the defendant has gained the trust of influential Americans. It is part of his business to do so."

The government said, moreover, that "it is reasonable to assume he (Truong) possesses the means and access for returning to the Socialist Republic of Vietnam," and there is " a distinct possibility he will flee."

At the hearing, McDermott suggested Truong could use "safe houses" in making his escape, and said that this man "who faces three life terms" for his alleged crimes in the U.S. would find "a completely safe haven" in Vietnam.

Meanwhile, the decision on Ronald Lewis Humphrey's earlier appeal for reduction of his $150,000 bond was made public yesterday in Richard. The appeal was denied.