After a high-speed car chase and shootout in Queens today, police searching for fugitives from Tuesday's Brink's holdup and triple murder killed one man and arrested a second as the investigation into a possible terrorist plot intensified.

Police identified the suspect who was taken alive as Nat Burns, 36, also known as Nathaniel Williams, of New Orleans. One of several Black Panthers indicted here in 1968 for a series of bombings, he had escaped prosecution by sliding down a drainpipe at his home as police approached.

The dead man was identified as Sam Smith, 37, also known as Mtajori Sandiata, whose criminal record dated to 1961 and included arrests for robbery, attempted murder and narcotics.

The gun battle took place just after noon.

At the same time, 25 miles to the north in Nyack, Weather Underground fugitive Katherine Boudin and three others arrested in Tuesday's Brink's robbery attempt were arraigned on murder charges in a setting that resembled an armed camp, with guards wielding submachine guns.

Earlier in the day, police reported discovering bloody clothing, floor plans for police stations and lists naming police officers targeted for killing, along with weapons, ammunition, walkie-talkies and radical literature in raids on what they described as several "safe houses" in Manhattan, the Bronx, Brooklyn and Mount Vernon, N.Y. The officers were following leads from the Brink's holdup, which led them initially to a "bomb factory" in East Orange, N.J., and seemed to suggest links with numerous other crimes committed in the area.

The investigators also pursued mounting evidence that the crimes were carried out by a faction of the Weather Underground and the Black Liberation Army, acting in concert.

According to authorities, the running gun-battle in Queens today began when police tried to stop a gray Chrysler LeBaron bearing a New Jersey license plate linked to a getaway car used in Tuesday's attempted robbery and seen on another car parked outside the Mount Vernon apartment raided earlier. The Chrysler sped up the Van Wyck Expressway and stopped suddenly near Shea Stadium. The two passengers reportedly jumped out and started firing.

Police fired back, wounding Smith fatally in the head. Burns gave up after his gun jammed, police said. Both were wearing bulletproof vests, and they carried at least one 9mm automatic and ammunition similar to those used in the Brink's heist.

Inside the Chrysler, police said, they found a Colt .380 automatic, 161 rounds of .223-cal. M16 ammunition, 80 rounds of .44 Magnum ammunition, 35 rounds of .30-cal. ammunition and a bag of rifle parts.

Boudin, 38, was captured Tuesday as she fled the $1.6 million Brink's holdup. Captured with her were Judith Clark, 31, of Manhattan, Samuel Brown, 41, and David Joseph Gilbert, 37, of Cambridge, Mass. All except Brown were linked to the Weather Underground.

Gilbert was identified by a former friend of Boudin in Chicago as the father of Boudin's baby son. In an account given to the Chicago Sun-Times, free-lance writer Robin Goldwyn said of her recent friendship with the woman who turned out to be Boudin: "She would come and go as she pleased, sometimes with 'Louis,' her companion and the father of her year-old son, Chesa. We were told that Louis worked as a mover."

Boudin preferred to live apart from "Louis," Goldwyn said. She added that he is the man identified as Gilbert.

Gilbert was listed by federal authorities as a fugitive member of the Weather Underground in 1975 and was once wanted in Colorado for arson and assaulting a police officer, The New York Times reported.

Brown has an arrest record in New York dating back to 1958 on burglary, robbery and weapons charges, the paper reported. He was arrested May 19 and charged with attempted auto theft and possession of a weapon and is scheduled to appear in court on those charges Nov. 2.

A getaway car that eluded police after the Tuesday ambush was located in Pelham, N.Y., and authorities said it was registered to Marilyn Jean Buck, 34, a fugitive who was sentenced in 1973 to 10 years in jail as a gun-runner for the Black Liberation Army. She is also listed in New York City police files as a member of the Weather Underground, The Times reported.

Late tonight in the Bronx, a man and a woman described as 1960s Weathermen were arrested in connection with a 1979 police raid on a "bomb factory" in nearby Hoboken, N.J. An FBI spokesman said he did not know if the two, who were arrested without incident, were linked to the Brink's robbery.

At the arraignment today, police officers stood on surrounding rooftops with automatic weapons as the four defendants were escorted into Village Justice Court in Nyack. German shepherd police dogs patroled the halls. All four defendants were ordered held without bail on charges of second-degree murder, the most serious possible in New York State. First-degree murder requires the death penalty, which has been outlawed in the state.

The hearing, attended by four prominent attorneys who have represented radical activists, was stormy. One of the attorneys present was Boudin's father, Leonard. He later said he had visited his daughter in jail and had taken her a shopping bag full of clothing. He told reporters he felt "torn between being a father and being a lawyer."

There were no outbursts from the defendants, who sat handcuffed with 14 police officers near them. The four looked weary and battered. Clark and Gilbert, who, according to testimony, were with Brown in the getaway car that crashed after the robbery, had black eyes.

Brown appeared the most badly injured. Wounded by gunfire in the exchange at the shopping center where the Brink's truck was making a pickup from a bank, Brown wore a neck brace, moaned throughout the four-hour proceeding and occasionally slumped, resting his head on Clark's shoulder.

Brown's condition prompted a series of outbursts--and at one point a screaming match--among defense attorney Susan Tipograph, Rockland County District Attorney Kenneth Gribetz, and Judge H. B. Lewis. The outbursts started when Tipograph made a request to the judge for medical attention for Brown, who she claimed had been beaten by police.

"My client has serious medical problems...he was taken from prison without shoes...It's an act of the most egregious malpractice," she said. "He was taken from his hospital bed and thrown on the floor of his cell and beaten repeatedly by police. He was beaten on his way to the doctor in jail and on his way back. I believe his life will be in danger."

The district attorney angrily denied her accusations.

Tipograph, however, returned to the subject again and again.

"He's in pain, he can hardly walk," she said at one point.

Little was heard from the defendants and little could be seen of their reactions. They were so surrounded by police that the only thing apparent at one point was four pairs of nervously tapping feet. All wore blue Rockland County prison jackets, the pale red faintly stenciled in blue. Gilbert, long-haired and bearded, at the far left of the line of defendants, smirked occasionally; Brown appeared unaware of much of what was happening around him.

There was little response from the best known of the four, Kathy Boudin, who has been underground for 11 years, ever since she was seen escaping from a Weather "bomb factory" explosion in a Greenwich Village townhouse. She whispered and smiled occasionally with Clark and smiled often at her father, who often spoke with her, at times crouching in front of her, once lightly touching her face with his hand as he passed.

Brown fared the worst of the four defendants. Det. Arthur Keenan of the Nyack Police Department, a witness to Tuesday's shooting death of two police officers, testified for the prosecution that he had seen Brown do the shooting. He also said that Boudin had emerged from the getaway van peacefully. A later witness, South Nyack Police Chief Alan Colsey, who apprehended Brown when he apparently moved on to another getaway car, testified that Clark, Gilbert and Brown offered no resistance.

Keenan, the partner of Nyack Sgt. Edward O'Grady, one of the two officers killed in Nyack, said on the stand that he and O'Grady were at headquarters when word came of a robbery and shooting at the nearby Nanuet Mall. A later radio transmission, he said, reported that the original getaway vehicle, a red van, had been discarded and that the suspects had transferred to a Honda and a U-Haul truck.

Keenan spotted both vehicles. Inside the Honda was a woman he identified as Clark. He told a team of officers to set up a roadblock at an intersection ahead. They did, and stopped the two vehicles. O'Grady, according to the testimony, checked the driver's side of the truck, at which point a woman Keenan identified as Boudin got out from the other side. "She put her hands up to her face," Keenan said. It is thought that the driver was among those who escaped.

Keenan left Boudin with O'Grady and two other police officers. Then, hearing noises from the back of the truck, he proceeded to the rear.

"I heard a noise coming from the U-Haul truck. When I turned and went back. I saw a black man with an automatic weapon shooting at me and two other officers--police officer Waverly Brown and Sgt. O'Grady--and I dove to the ground with my weapon drawn and rolled 30 feet and returned fire...."

Keenan, though hit in the exchange, saw Brown fatally shoot the two officers, he said. After that he saw a white vehicle "take off very fast." By the time he picked himself up, Boudin had been captured by an off-duty New York City police officer.

As the police drama unfolded, a clearer portrait emerged of Boudin's life up to her capture.

Calling herself Lynn Adams, she appeared to have been leading a relatively mundane existence as a welfare mother in a six-story co-op near Manhattan's Columbia University, saying she worked nights as a waitress and taking her baby on bike rides.

Much of the information about Boudin came from Rita Jensen, a reporter for the Stamford (Conn.) Advocate, who revealed Thursday that she and Boudin had been roommates for three years. Jensen said she did not learn Boudin's true identity until after the arrest.

As journalism became a part of the story, and some editors agonized about the ethical questions raised by a reporter's involvement in a sensational crime story, New York Post publisher Rupert Murdoch took the direct approach. He will "pay anything for Rita's story, will match any offer and do better," a Murdoch spokesman said.

Jensen became the focus of questions yesterday as her own newspaper called attention to inconsistencies between her account and that of her mother about how long she had known Boudin. The paper also raised questions about the extent of her knowledge about her roommate's links with radical political groups.

Since early 1980, Boudin has collected welfare in New York City under the name of Lydia Adams, according to officials. Since her baby's birth in August, 1980, "Adams" has been receiving $177.75 every two weeks in public assistance, including $91.50 as rent allowance.

The cost of the apartment, owned by Jensen, is about $105,000, according to one resident. Maintenance runs between $200 and $250 a month.