Authorities Friday awaited the results of tests to determine if two letter bombs this week that injured university professors in Connecticut and California were connected and possibly linked to similar terror bombings in the late '70s and early '80s.
Officials at higher education facilities around the nation, meanwhile, were alerting personnel and mail handlers to watch for strange packages.
The FBI said the composition of the bombs that went off at Yale University and near San Francisco are being tested to determine if there is physical evidence to establish a connection between the explosions.
'If the composition of the bomb in New Haven is similar to the one (in San Francisco), we'd be able to establish a connection with more confidence,' said Rick Smith, an FBI spokesman in San Francisco.
He said officials are also checking possible connections to a dozen unsolved parcel bombings involving academics and computer specialists in the late 1970s and early 1980s.
'The victims are similar and there are some forensic similarities,' Smith said.
The New York Times Friday reported it had received a letter from Sacramento, Calif., that was postmarked in June, warning of an upcoming 'newsworthy event' and claiming to be from 'an anarchist group calling ourselves FC.'
Authorities believe FC is also responsible for the dozen package bombs since 1978 in what became known as the Unibomb case, for University Bomber.
The Times said the bomber's distinct signature was clear from the material used to make the bombs, which is what the FBI laboratory in Washington, D.C., is trying to determine from the latest two bombings.
There also may be a 'genetic' connection to the two incidents and a threat at another Connecticut facility.
Injured in Thursday's blast was David Gelernter, 38, director of undergraduate computer science studies at Yale. He was listed in serious condition with chest, face and hand injuries suffered when a package exploded in his hands in his fifth floor office on the Yale campus.
Officials were checking to see if perhaps the package was sent to the wrong Gelernter because his sister-in-law, Cheryl Gelernter, is a postdoctoral fellow in genetics at Yale.
'That puts her in the same ballpark as the San Francisco victim,' the Boston Globe quoted one investigator as saying.
On Tuesday, Charles Epstein, 59, head of genetics at the University of California in San Francisco, lost several fingers on his right hand when a package delivered to his suburban home in Tiburon exploded. Epstein, one of the nation's leading researchers into the causes of Down's syndrome, was reported in fair condition at Marin General Hospital.
Gelernter's brother, Joel, is a Yale psychiatrist who has conducted research in genetics. Joel works at a Veterans Administration hospital in West Haven, Conn., which reportedly received an anonymous call Thursday from a person who said, 'You're next' and hung up.
David Gelernter invented an innovative computer programming language he named Linda, after the pornography star Linda Lovelace. The language makes it possible to link small computers to work on a single large problem, effectively nibbling at the problem in what he called 'piranha processing.'
FBI Director William Session said Thursday his agency has alerted all of the nation's universities to be on the lookout for suspicious packages.
'I don't think it's illogical for people to suggest that there may be a link' between the bombings, Sessions said. 'This has to be of concern to people in the scientific research area.'
Harvard and the Massachusetts Institute of Technology, along with other universities around the nation, have alerted mail handlers and personnel to be cautious with suspicious packages. MIT campus workers were reported to be 'horrified' by the bombings.