The two suspicious packages were oddly shaped, clumsily wrapped and had no return addresses on them.
So nervous mail processors at UC Irvine notified campus police, who promptly called the Orange County Sheriff's Department bomb squad.
As it turned out, both small packages contained only thermometers--a promotional gift from a credit card company. But the items had come to the campus shortly after a UC San Francisco genetics professor and a Yale computer scientist were badly injured late last month when packages mailed to them exploded.
These days at UCI, where 25,000 letters and packages arrive daily, no one is taking any chances with unusual-looking mail.
"We've told everyone that no matter what a letter or package looks like, if they feel that something is not right for whatever reason, they should call us and we'll have it checked for them," said Kathy Stanley, chief of campus police.
Immediately after the UCSF and Yale bombings, UCI officials circulated a memo on campus and at the UCI Medical Center in Orange warning faculty and staff members to "exercise reasonable caution in handling mail and packages that appear unusual."
In the past two weeks, the U.S. Postal Inspection Service has sent representatives to UCI and Cal State Fullerton, where they have given presentations to mail-room employees on how to detect a possible bomb and what to do.
The most obvious clue, according to postal officials, is a parcel or letter that feels rigid or appears lopsided or bulky. Next, they advised, be wary of mail with no return address.
The urgent memo and the postal presentations are designed to provide mail workers and recipients with some guidelines and precautionary measures, university officials said. They are not meant to instill fear or paranoia.
"We just try to make everyone aware and . . . responsible," Stanley said, adding that campus security has not been tightened. "We just want everyone to have a heightened sense of awareness" of the possible danger.
Almost three weeks after the twin bombings, faculty members and mail-room employees at UCI are not quite as edgy about coming into contact with the mail.
But a wariness remains, many said, and they don't know when, or if, it will fade.
"I've always been careful about my mail, but I've been particularly cautious since UCSF and Yale, particularly since it seems the science departments are being targeted," said Gregory Benford, a physics professor.
For Benford and others, the explosions were a sinister reminder of what has happened on other campuses since the late 1970s.
From 1978 to 1987, there were 12 such bombings across the country--half of them involving college faculty members. Federal authorities say the bombings, including the two most recent ones, are the work of one man, but they have neither suspects nor strong possible motives.
In the first of the two latest incidents, UCSF geneticist Charles Epstein, 59, lost several fingers and suffered injuries to his chest, abdomen and face when he opened a parcel addressed to him in the kitchen of his home on June 22.
Two days later, David Gelernter, 38, an associate professor of computer science at Yale, was injured when he opened a packaged bomb in his office on campus.
The problem, some UCI professors believe, is that on any given day, they receive so many pieces of mail that, short of an X-ray machine, there is no reliable way to know if a letter contains explosives.
"You're going to get mail, and it has to be opened, so the main problem is you're now aware of the possibility of receiving dangerous mail, but what can you do?" Benford lamented. "I don't know of anyone who has gotten past this anxiety, but you can't let caution or fear paralyze you. You go on."
In the UCI mail room, where letters and packages make their first campus stop, things are getting back to normal. Almost.
Here, supervisors reluctantly agreed to discuss the campus mail operation but declined to talk about exact procedures, saying it is too soon after the two most recent incidents. They did not even want to disclose, albeit generally, who the packages containing the thermometers were intended for.
Yet they acknowledged that mail-room workers are experiencing more stress lately.
"Because the (mailed) bombs are random and arbitrary and appear to focus on universities, the employees here in the mail room have some vulnerability," said Lynn McLeod, manager of support services and special assistant to the vice chancellor of administration. "We just don't want anything to contribute to this."
In a tan building away from the hubbub of the campus, the UCI mail facility is run by nine full-time employees who sort through and deliver the estimated 25,000 packages and letters daily. The small building is cramped, with hundreds of bags and boxes of mail, bins and an electronic mail sorter.
Every day, the U.S. Postal Service makes two deliveries to the facility by noon, and processors sort the mail and distribute it to the departments within the same or next day. Campus mail workers do their job quickly and systematically, now more aware that potential danger could involve them.
"I don't think the job is stressful at all--until you start hearing about other people being hurt opening the mail," said a 34-year-old processor as he emptied bags of mail into bins. "Of course, everything comes to us before it goes to anyone else, and that sometimes makes me nervous."
The processor was the only one who agreed to be interviewed, and campus officials insisted that he not be identified.
"My one consolation," said the processor, "is that we don't actually open the mail, and we're pretty much assured that things are detonated by being opened."
While that fact is precisely what has some professors scared, they have tried to put the situation into perspective.
"I guess until whoever is responsible is caught, a few of us will continue to be nervous," said chemistry professor George Miller.