The Japanese Red Army, dormant for years after a decade as one of the world's most feared terrorist groups, is back in the news because of charges that its members bombed a USO club last week in Naples, Italy.

The car bombing, which killed an American and four Italians, was one of several recent reports of activity by the group, whose operations in the 1970s included the Lod Airport massacre in Israel.A Japanese man arrested April 12 on the New Jersey Turnpike with pipe bombs in his car is suspected of being a Red Army member, the Foreign Ministry says.

Last November, a Red Army fugitive was arrested after arriving in Japan with a ticket for South Korea, site of the 1988 Summer Olympics.

Japanese experts and Italian police believe the Red Army's current leader is Fusako Shigenobu, 42-year-old daughter of a Tokyo insurance salesman, who once worked as a bar hostess in Tokyo to raise money for the terrorists.

She dropped out of college in the '60s and married as part of a plan to slip out of Japan, allegedly for a mission that led to the Lod massacre in May 1972. Two of the three attackers, including her husband, were among the 28 people killed.

Police in Japan said she sent letters from Algeria before the Lod attack, telling friends: "I have become a member of a new guerrilla organization, and we are preparing a historic fight at the end of May."

After the slaughter, police said, she wrote in a letter: "The heroic actions of the three Japanese revolutionary fighters are highly valued."

Her father, Sueo Shigenobu, was quoted in a 1972 newspaper interview as saying he and his daughter had argued heatedly about politics.

"She would not change her stand on the Sekigun (Red Army) principle of staging simultaneous uprisings all over the world," he said.

Shigenobu and others led an extremist splinter group away from the now-defunct General Federation of Japanese Students, or Zengakuren, in 1968.

The goal of what they originally called the United Red Army was "a simultaneous world revolution to destroy capitalism and imperialism."

Masayuki Takagi, a commentator on Japanese police and security matters, said Shigenobu probably brought in more funds as a bar hostess than were contributed by any of the Red Army's other 300 members.

Official crackdowns on the group increased in 1970 after nine Red Army men, some armed with samurai swords, hijacked a domestic Japan Air Lines flight to Pyongyang, capital of communist North Korea. Eight of the hijackers still live in North Korea, and the ninth is said to have died there last year.

In February 1971, Shigenobu married Tsuyoshi Okudaira, a 25-year-old leftist student who, unlike his bride, was not wanted by police. Soon after their marriage, they got through airport security and flew to Beirut.

Takagi said Shigenobu organized the "Mideast Arab Detachment" of the Red Army that year. The organization has nearly disappeared in Japan since and is based in the Middle East with close ties to Arab terrorists.

Shigenobu is said to be a close friend of Leila Khaled, an Arab woman involved in several airplane hijackings in the 1970s.

The Red Army, believed to number 30 to 40 people, is intensely loyal to imprisoned comrades. In the 1970s it hijacked several airliners and bargained successfully to free Red Army members.

Kozo Okamoto, the survivor of the Lod attack, was sentenced to life in prison, and Shigenobu spoke several times of her hopes to free him.

"My thoughts have always been on freeing comrade Okamoto," the Tokyo daily Asahi quoted her as saying in a clandestine 1981 interview. She added, however, that the Red Army lacked "the material or manpower to carry out the operation immediately."

In 1985, Israel freed Okamoto and 1,100 other prisoners in an exchange for Israeli soldiers held prisoner by Arabs. Since then, he and Shigenobu have been photographed in Lebanon.

In a letter released by Japanese police in 1984, she said she and Red Army comrades were "all back in the front line of the Bekaa Valley" of Lebanon, a Syrian-occupied area long used for training Arab and other guerrillas.

She said the Red Army had not abandoned violence as a means of "fighting imperialism."