The Science Center was evacuated Tuesday afternoon in the latest of a series of false bomb scares, officials said this week.

After a suspicious abandoned package was reported by a staff member at the Science Center, administrators called fire and police departments and the building was evacuated from about 4:30 p.m. to 8 p.m., Science Center Director Nona D. Strauss said this week.

"It appears someone left it...in the arcade," Strauss said. "We had a little bit of excitement."

She said the Science Center staff called the Harvard police and the Cambridge fire department, who came to check out the package. After examining it, they decided to call the Cambridge bomb squad and to evacuate the building.

The package turned out to be merely a briefcase left behind accidentally.

But, according to Lt. John F. Rooney of the Harvard Police, the package was considered suspect enough to call in further reinforcements. "It was X-rayed by the Boston bomb squad," he said. "The circumstances were unusual, but it was harmless."

Rooney said there have been several alarms about suspected bombs in the past few weeks, ever since the University sent out a flyer to all students, faculty and staff warning them about two letter bombs sent to research universities around the country.

The first bomb scare at Harvard was reported on Monday, June 28 by Dean of the Faculty Jeremy R. Knowles, who received an unusual package at his house on Bryant St.

Since then, Rooney said, the Harvard police have received warnings of suspicious packages at both administrative and residential buildings.

Although none have contained explosives, he said, all have been treated with extreme caution.

Rooney said the owner of the forgotten package, which contained only papers, was eventually tracked down, and the package was returned.

Rooney said Harvard has not been the target of any bomb threats recently, and he said police have no reason to suspect that Harvard would be a particularly favored target of the serial bomber.