A former Vietnamese ambassador and his wife, who both had resigned diplomatic posts in the United States in 1963 to protest repressive policies symbolized by their daughter, Mme. Ngo Dinh Nhu, were found dead yesterday in their Washington home.

Police said they had not determined the cause or manner of the deaths of the couple, Tran Van Chuong, 88, and his wife, Nam-Tran Chuong, 75, and that homicide detectives were investigating.

The bodies of the Chuongs were found about 10:50 a.m. in their two-story brick house at 5601 Western Ave., in upper Northwest Washington, where they had lived quietly and inconspicuously for at least a dozen years.

Mr. Chuong resigned his post as South Vietnam's ambassador to the United States Aug. 22, 1963, accusing the government of Ngo Dinh Diem of totalitarian tactics and of brutal suppression of Buddhists.

At the same time, Chuong's wife resigned as South Vietnam's permanent observer to the United Nations.

The Chuongs' daughter, Mme. Nhu, was Diem's sister-in-law. Her husband, Ngo Dinh Nhu, was widely regarded as the power behind the throne during the Diem regime, and in recognition of the perceived ruthlessness of her participation in affairs of state she was known as the "dragon lady."

One homicide investigator said there was no obvious indication of the cause of death of either of the Chuongs.

He said "there is nothing to lend itself to any" theory about the case "one way or the other." In particular, he indicated, there were no signs in the house of forced entry or of violence.

One neighbor said she had heard Tran Van Chuong was in poor health, but details were not available.

The bodies were taken yesterday to the D.C. medical examiner's office and autopsies are expected to be performed there today.

One homicide investigator said both Chuongs had been seen alive yesterday by a relative, said to be a son or daughter. The investigator also said it was believed that a relative, possibly the same one, discovered the bodies yesterday morning and telephoned police.

The relative could not be located for comment last night.

The conflict of the early 1960s between the Chuongs and the Diem-Nhu regime was widely publicized after the Chuongs' resignations, and appeared particularly painful for the couple.

In his letter of resignation to Diem, Chuong took issue with the contention of his daughter and her husband that a crackdown on the Buddhists was necessary because of their growing opposition to the Diem-Nhu regime.

Earlier, Tran Van Chuong's embassy had issued a news release disavowing his daughter's anti-Buddhist statements and accusing her of a "lack of respect" for South Vietnam's Buddhist majority.

At the time of his resignation, Chuong described himself as a Confucian. His wife was known as a devout Buddhist. Their daughter was converted to Catholicism.

"This is a great misfortune for my country, for my family and for my religion," Nam-Tran Chuong said in an interview the day after the resignations.

She said that as parents of Mme. Nhu, she and her husband had received many complaints about persecutions of Buddhists. Although she had written about it to Diem and Nhu and to her daughter, she said, they never talked about the complaints in their return letters.

"They write only of family matters, of my grandchildren," she said.

On Nov. 1 and 2, 1963, a coup toppled the South Vietnamese government and Diem and his brother were killed. Mme. Nhu fled and, according to The Associated Press, settled in Italy.

The Chuongs were both members of prominent Vietnamese families. He was trained in law in Paris. She was a descendant of Vietnamese royalty.

In exile in Washington, a neighbor on Western Avenue said, "they kept very much to themselves."