Yale Professor Is Injured by Blast; Mail Bomb Tied to Terror in 70’s

A prominent computer science professor at Yale University was critically injured yesterday by a mail bomb that Federal officials said marked the re-emergence of a mysterious bomber who terrorized campuses and high- technology companies around the country in the 1970's and 80's.

The package exploded shortly after 8 A.M. at the computer science center at Yale in New Haven. The authorities said they believed it had come from the same person who sent a bomb to a professor at the University of California at San Francisco on Tuesday and who has sent 12 other similar packages since 1978. A Group Called 'FC'

Scores of law-enforcement officials have tried for years to track down the bomber, whom they called Unibom, for University Bomber. The authorities have never been able to establish a motive or precise pattern to the bombings, but officials said yesterday that the bomber's distinct signature was clear from the material used to make the bombs. They also made the connection to the earlier incidents from a letter received yesterday by The New York Times.

The letter, which was postmarked June 21 from Sacramento, Calif., warns of "a newsworthy event" and identifies its author as "a group calling ourselves FC." It promises to "give information about our goal at some future time." The authorities said the bomber had previously identified himself as FC.

William S. Sessions, the Director of the Federal Bureau of Investigation, said this evening that the agency had sent a message by computer network to most universities to be on the alert for suspicious packages. At a news conference in San Francisco, Mr. Sessions said professors should be particularly cautious about any packages with excessive postage, incorrect titles, misspellings of common words or no return address.

The bomb yesterday went off in the hands of David Gelernter, the 38-year-old director of undergraduate studies in computer science at Yale. Moments after the bomb exploded, ripping off his shirt, he ran from his fifth-floor office at Yale's computer science center building to a health clinic a block away, leaving a trail of blood. Witnesses said they could hear the explosion throughout the building. Professor Undergoes Surgery

Professor Gelernter's condition was upgraded from critical to serious yesterday afternoon after surgery at the Yale-New Haven Hospital. He suffered severe wounds to his abdomen, chest, face and hands.

Mr. Gelernter, who had studied to become a rabbi, is best known for inventing an innovative computer programming language he named Linda, after the pornography star Linda Lovelace. It has attracted a wide following in both the scientific world and for its commercial applications in publishing and computer animation. He has also expressed a strong commitment to applying computer technology to a wide array of social and economic problems.

Officials said that after the bombing, the switchboard at the Veterans Affairs Medical Center in West Haven received a call from someone who said, "You are next."

Professor Gelernter's brother, Joel, an assistant professor of psychiatry at the Yale Medical School, works at the medical center, but Assistant Chief Dean Eserman of the New Haven police said the authorities did not know if the bombing and the phone threat were related.

Joel Gelernter is also a specialist in genetics, and last night the authorities said they did not know if threats to him were also connected to Tuesday's bombing in California, whose victim was a geneticist.

That victim was Charles Epstein, who lost several fingers and suffered a broken arm and severe abdominal injures when he opened a padded brown envelope at his home in Tiburon, near San Francisco. Dr. Epstein, 59, continued recuperating yesterday. He is widely known for his research into Down syndrome and other genetic conditions and heads the university' division of medical genetics. String Dating to 1978

Law-enforcement officials said yesterday that they believed the mail bombs were the latest in a series of deadly parcels that have been mailed or placed by the bomber since May 26, 1978. The bombs have injured 21 people and killed one, Campbell Scrutton, the owner of a Sacramento computer shop, on Dec. 11, 1985.

While the bombs apparently have been sent mostly to people who workedextensively with computers and in high-tech fields, investigators have been at a loss to establish a more concrete pattern and motive. Some of the packages were addressed to a particular person, but others were left in parking lots or on doorsteps. The bomber has occasionally sent letters advising intended victims that packages would soon be arriving.

Three Federal agencies and scores of local law-enforcement officials have spent years trying to track down the bomber, who is also believed to have been behind bombings at universities in California, Illinois, Michigan, Tennessee and Utah. In 1980, he sent a bomb to the Lake Forest, Ill., home of Percy A. Wood, president of United Airlines, cutting and burning his hands and face. The bomb was planted inside a novel, "Ice Breakers." Wide-Ranging Inquiry

The bomber also mailed an explosive device in 1985 to the Boeing Aircraft Company plant in Auburn, Wash. It did not injure anyone.

The authorities say the bombs have become progressively more complex over the years and they tend to be meticulously constructed of common materials like fishing line, string, nails and wrapping paper. The shards in each explosion have been similar enough to lead investigators to conclude that they came from the same person.

In an attempt to crack the case, the authorities have held conferences over the years about the bomber and have combed through thousands of names supplied by victims. The case has been jointly handled by the Bureau of Alcohol, Tobacco and Firearms; the Federal Bureau of Investigation, and the United States Postal Service.

Officials say the biggest break in the long-running investigation came on Feb. 20, 1987, when the bomber placed his 12th bomb, the last once before this week. It was in a burlap bag in a parking lot of CAAMS Inc., a computer sales and service company in Salt Lake City. When Gary Wright, an employee of CAAMS, tried to move it, it exploded and he received fragmentation wounds to his leg, hand, arms, throat and face.

But before the bomb went off, the authorities say a witness observed a white man putting the device between two parked cars. He was described at the time as between 25 and 30 years old, around 5 feet 10 inches to 6 feet tall, and weighing 165 pounds, with reddish-blond hair, a thin mustache and a ruddy complexion.

The authorities say the bomber's first attack, in 1978, was in a technology building at Northwestern University in Evanston, Ill. A security guard was injured in that incident. A year later, a graduate student at Northwestern's Chicago campus was burned when he opened a cigar box containing an explosive device.

On Nov. 15, 1985, a bomb exploded at the Ann Arbor home of James McConnell, a psychology professor at the University of Michigan. The blast injured a research assistant who opened the textbook-sized package. The parcel was addressed to Professor McConnell and was postmarked in Salt Lake City.

Altogether, 12 of 14 bombs that the authorities say were sent by the bomber have exploded and in all but one of those instances someone has been hurt. The most damaging explosion occurred on an American Airlines flight from Chicago to Washington in November 1979, when a bomb exploded in the airplane's cargo section. The plane made an emergency landing and 12 passengers suffered smoke inhalation.

The letter sent to The Times, which investigators say came from the bomber, said:

"We are an anarchist group calling ourselves FC. Notice that the postmark on this envelope precedes a newsworthy event that will happen about the time you receive this letter, if nothing goes wrong. This will prove that we knew about the event in advance, so our claim of responsibility is truthful. Ask the FBI about FC. They have heard of us. We will give information about our goals at some future time. Right now we only want to establish our identity and provide an identifying number that will ensure the authenticity of any future communications from us. Keep this number secret so that no one else can pretend to speak in our name."

It then gives a nine-digit number.

There was a feeling of nervousness at Yale yesterday as postal workers on the campus and in New Haven checked for suspicious packages. The newly named president of the university, Richard C. Levin, met with faculty members to reassure them about security.

"There is concern on campus," said Sheila Wellington, secretary of Yale University. "But there does not appear to be fear. There is nothing approaching a crisis circumstance."