Emile Cardinal Biayenda, archbishop of Brazaville and primate of the Congo, was taken from his home during the night and murdered, the government announced today.

A communique blamed the killing on former President Alphonse Massamba-Debat, who has been charged with being behind the assassination last Friday of President Marien Ngouabi.

Massamba-Debat, whom Ngouabi overthrew in 1968, is already under arrest, and the government has launched a search for the killers of the president and, now, the cardinal.

Biayenda, 50, was one of the eight black African cardinals. He had met with Ngouabi only an hour before four gunmen burst in on the president and killed him. Today, church sources and the Congolese government alike stressed that relations between Ngouabi, and the cardinals had been good.

There was speculation that Biayenda's kllling may have been tribally motivated: The first government announcement said the killers were three members of Ngouabi's "family," but the term is often used here to refer to tribes. The Congo has been racked by tribal violence since it gained independence from France in 1960.

Biayenda was the second Catholic cardinal to be murdered in this century. The Spanish archbishop of Saragoza, Juan Cardinal Soldevilla, wa ambushed and shot to death by anarchists on June 4, 1923, during a church-state conflict.

In Rome, Pope Paul VI - who made Biayenda a cardinal in his last consistory, in 1973 - announced the "bitter and sad news" at his weekly general audience and later officated at a special requiem before 6,000 pilgrims.

The military committee that has ruled the Congo since Ngouabi's death said the president and the cardinal had "lived and died serving the same cause. They died through the fault of a single man . . . the sinister massamba-Debat." It added that "an examplary punishment will be meted out" to the former president "and his accomplices."

"He who lives by the sword shall die by the sword, and he who kills by fire will die by fire," a government communique said.

Radio Brazzaville said, "Every Congolese remembers the harassment to which the Congolese church was subjected throughout the rule of this wretched figure," Massamba-Debat.

The government claims that the former president has confessed that he was behind Ngouabi's murder, in a bid to regain power.During Massamba-Debat's five years in office both Ngouabi and Biayenda spent more time in in prison.

Cardinal Biayenda was ordained in 1958 and made archbishop of Brazzaville 13 years later.

Sources in the Vatican said that although the cardinal and Ngouabi were from rival tribes from opposite ends of the country, they had mutual respect and good working relations. The sources credited Ngouabi, a Catholic, with improving church-state relations during the nine years he held power.

Forty per cent of the Congo's 1.3 million peopl are Christian, most of them Catholic.

Cardinal Biayenda, who had approved of Ngouabi's Marxist and pro-Soviet policies, said in 1971: "Socialism is the only solution able to establish the order of justice."

Radio Brazzaville stressed that the cardinal's appointment with the president the day the latter was killed had been a regularly scheduled conference.

Biayenda's death reduces the number of cardinals to 133, of whom 115 are under 80 years of age and therefore able to take part in electing a new Pope.

Until Cardinal Soldevilla's death in 1923, no Catholic cardinal had met a violent death in more than three centuries.

A Vatican historian said Italian Carlo Cardinal Carafa was executed by strangulation in the Vatican prison on orders of Pope Pius VI in 1561 for high treason and murder.

St. John Fisher, an English cardinal jailed for refusing Henry VIII as head of the English church, was tried for high treason and executed in 1535.

The largest group of cardinals ever to meet violent death were five cardinals killed in obscure circumstances after Pope Urban VI imprisoned them for their support of anti-Pope Clement VII in 1385.

Several cardinals were tried and jailed by Communist governments in Easter Europe and China after World War II. Yugoslavia's Aloysius Cardinal Stepinac died of a blood diseas while in prison in 1960.