Former United States Information Agency employe Ronald Humphrey and Vietnamese expatriate David Truong, who had been a leader of the antiwar movement here, were convicted yesterday of spying for the Socialist Republic of Vietnam.

A jury in federal court [WORD ILLEGIBLE] found both Humphrey and Truong guilty of espionage, theft of government documents and "conspiracy to injure the national defense of the United States."

Humphrey had admitted during the trial that he took documents that crossed his desk at the USIA and gave them to Truong, who then gave them to a supposed courier for the Vietnamese government. The courier turned out to be a double agent who was the principal witness against the two men.

As the last part of the jury's verdict was read aloud in the courtroom filled with the silently weeping relatives and friends of the two men, and the jurors began to file out, Humphrey's father leaped from his seat, clutched the railing that divided him from his son and shouted to Judge Albert V. Bryan Jr.

"Your honor," Louis Humphrey pleaded, "May I please take my son's place in jail tonight? He will need love and understanding tonight. May I please take his place, your honor?"

"No, you may not," Bryan said as the convicted American's mother, Leah Humphrey and Kim, a Vietnamese whom he calls his common-law wife, attempted to pull the grief stricken father back into his seat.

"No, no, no," Mrs. Humphrey said, crying, to her husband.

Three of the jurors began crying as Bryan adjourned the proceedings and Humphrey and Truong were taken quickly from the courtroom. Truong's sister attempted to reach out to touch him and began crying, "David, David." Marylou Humphrey, Humphrey's estranged wife, stood silently at the rail.

"It was a rip-off," Leah Humphrey said outside the courtroom. "The government lied. They lied through their teeth. It was just a political thing."

Kim, Humphrey's Vietnamese common-law wife stood in front of television cameras outside the Alexandria courthouse and shouted, "They didn't do anything wrong. I got him in trouble. I was jailed (in Vietnamese prison camp) for 225 days. I gto him in trouble."

The jurors deliberated about 14 hours before finding the two men guilty of all possible charges in the unprecedented case. When the verdict was read Truong stood facing the jurors in silence. Humphrey became ashen and hung his head. They each face possible life imprisonment.

While both men admitted their role in transmitting the documents, they testified during the 11-day trial their motives were not criminal. Humphrey said he did it out of his love for Kim - he thought that his aiding Vietnam would help secure her release from Vietnam (as she ultimately was). Truong said he sent documents, cables and books to the Vietnamese in a continuing effort to improve relations between the two countries that reached back 10 years.

Jury foreman Robert Charlesworth, a retired American Telephone and Telegraph account manager, said, "I felt sympathy for all of (the defendants). We all did. But you can't play emotions; that wasn't the question here. We knew why (Humphrey) did it, but that doesn't excuse it in any way."

"You just kind of go strictly by the law," a second juror said. "There was nothing else we could do."

"Needless to say we are extremely disappointed in the verdict," said one of Humphrey's three attorneys, Warren L. Miller. "We felt the jury would have been much more discerning that it was."

The unprecedented trial - the only espionage case to-come to trial in connection with the Vietnam war - has now set the stage for two possible constitutional tests, in appeals the lawyers said they probably will file.

The case has raised the question about the extent of the President's authority to authorize warrantless electronic surveillance during a national security investigation. In March Bryan ruled that key information from warrantless searches and electronic surveillance approved by President Carter and Attorney General Griffin B. Bell could be used in the case.It was the first time that a federal court considered the direct introduction of criminal evidence obtained without warrants during a national security investigation.

"If the government hadn't allowed this information "obtained without warrants, "Mr. Humphrey would be an innocent man," defense attorney Warren Miller said outside the courtroom yesterday.

"If this can go on and my son can be convicted in this manner then you can have your telephone bugged, too," Louis Humphrey told reporters outside the courthouse.

Bryan, who didn't set a date for sentencing, revoked Truong's $250,000 bond, which has been raised by his sister, church groups and other supporters. Humphrey, who was unable to raise $150,000 bail, also was ordered held without bond by Bryan.

Throughout the trial, defense lawyers concentrated on attacking the credibility of the key prosecution witness, 32-year-old Dung Krall, a CIA-paid informant, who acted as a courier between Truong and the Vietnamese in Paris.

But U.S. Attorney William B. Cummings said yesterday that the verdict "restored the credibility of Mrs. Krall. She's a courageous woman. She exposed herself to harsh attacks. Her credibility was very seriously attacked."

Throughout the trial, the 75-person capacity courtroom was packed with spectators, many from the Vietnam Trial Support Committee. This group, made up mainly of former antiwar activists, was formed to "assure an adequate defense for David Truong" and to protest the government's investigation and prosecution of the espionage case.

Members of the committee helped raise money to post bond for Truong, but Humphrey has remained in jail since the pair was arrested Jan. 31.

The split between the two defendants became apparent during the trial. On the last day of testimony Humphrey's attorney turned on Truong, eliciting the information that Truong had once kept extensive notes on how to recruit spies. In an effort to sever his client from Truong, he tried to prove that Humphrey was an "unwitting dupe" of Truong: a man tortured by his love for his Vietnamese mistress, Kim, and her family who were trapped in Vietnam.

Humphrey never denied taking cables from the USIA and giving them to Truong. He took the stand to testify that he did it to improve relations between the U.S. and Vietnam in some vague and indirect way. He testified that he hoped, as a result, that the Vietnamese would release Kim and her five children. He testified for more than an hour about his love for Kim until the judge cut him off, saying, "Let's get on with the merits of the case."

Attorneys argued for several days over whether the cables were properly classified and whether Humphrey and Truong were well-intentioned men or secret agents for Vietnam.

Humphrey testified he knew it was wrong to steal the cables and he knew that the documents had been classified but he figured it was only a state Department security violation and not a crime.

Truong said he sent the information to Vietnamese friends in Paris to use in their newsletter. His goal was to help normalize relations between the United States and Vietnam, he testified, not to harm the United States or give the Vietnamese an edge in negotiations with the U.S., as the government charged. Truong testified he was never a foreign agent and was never paid for distributing informations.

On opening day of the trial the key prosecution witness Dung Krall, testified that she delivered packages given to her by Truong to Vietnamese officials who called Truong "one of our people in Washington."

Krall's testimony was the only link during the trial to United Nations ambassador Dinh Ba Thi, who was named an unindicted coconspirator in the original indictment, and was asked to leave the country as a result. She testified that on one occasion Truong told her that Thi "doesn't know how to speak discreetly on the telephone. Mr. Thi doesn't know that the U.S. is a hostile country to Vietnam."

"You mean; Mr. Thi asked you to send the documents over the telephone?" Krall testified she asked Truong.

"Yes, he did," Krall testified Truong replied. "I already explained to him and I'm sure it won't happen again on the telephone."

On one occasion Krall testified she met Thi in New York. At that time the ambassador told Krall, "tell (Truong) to send the same thing he's been sending."

Krall, whose CIA code name was Keyseat, testified how she met Truong in different locations such as the Hecht Co. parking lot and Landmark Shopping Center in Alexandria to pick up the packages she delivered to the communists.

She masqueraded as an import-export businesswoman when contacting Truong, Krall testified, and delivered packages to the Vietnamese in Paris from Truong in September 1976, April 1977 and June 1977.

On one trip one of Truong's packages was given to two men wearing Ho Chi Minh pins, but Krall said she did not know who the men were.

"Guilt by jewelry," defense attorney Michael E. Tigar said, as he jumped to his feet to object to her characterization of the men. During his closing argument prosecutor Cummings said the men were members of the Vietnamese delegation to the Paris negotiations.

Because of information supplied by Krall, the Justice Department authorize a warrantless tap on Truong's telephone shortly before May 9 last year that recorded 567 phone conversations.

Three days later President Carter authorized the opening of packages and letters from Truong without a warrant. A microphone was installed in Truong's apartment May 23.

The telephone tap picked up conversation between Truong and Humphrey during which the two agreed to meet. President Carter then authorized closed circuit television surveillance of Humphrey's USIA office.