A suspicious bag that caused a bomb scare and closed down portions of the Yale Law School for several hours Saturday afternoon was determined to be harmless, University police said.

The Law School was holding a conference Saturday entitled “The Legacy of Brown v. Board of Education: Reflections on the Last Fifty Years,” which included a speech by former First Lady and New York Senator Hillary Clinton. Police believe a conference attendee left the bag in a women’s room in the basement of the school.

The scare did not disrupt the conference, Law School spokeswoman Janet Conroy said. The bomb scare is the second such incident in under a month.

A Law School employee notified University police about the bag at 12:28 p.m., Yale Police Chief James Perrotti said. Police and fire officials closed the front entrance and basement of the Law School, and roped off portions of High and Wall streets while they investigated the bag.

Police x-rayed the package and examined its contents. At 2:45 p.m., they announced the package was not dangerous and reopened the closed portions of the law school and surrounding roads. Clinton and her Secret Service unit arrived at the Law School without incident at about 3 p.m.

Members of the New Haven and Yale Police Departments, the New Haven Fire Department and the FBI investigated the package. The city’s Hazardous Devices Unit, an officer in a protective bomb suit, and a bomb-sniffing dog were involved.

Police initially completely closed entry into the Law School. Conference attendees and panelists were eventually allowed to enter the Law School through the school’s Tower Parkway entrance. Most of the law school remained open throughout the incident, Law School Associate Dean Mike Thompson said.

Perrotti said police believed the bag, which included a train schedule and conference itinerary, was probably left in the women’s room by a conference attendee who changed clothes in the bathroom and intended to pick up the bag later.

“They’ll be surprised it won’t be there,” Perrotti said.

There was no identification found in the bag, Perrotti said, and its owner could not be identified as of Saturday afternoon.

Perrotti said police followed detailed procedures in dealing with the package.

“You can’t cut any corners. You have to do it by the book for everyone’s safety,” he said. “It’s a little inconvenient but it’s better to be safe.”

The incident comes a month after the discovery of a suspicious package March 7 in front of Woodbridge Hall. That item, which police now believe was left accidentally after a meeting of the Yale Freestyle Dueling Association, was also determined to be innocuous.

A pipe bomb exploded in the Law School May 21, causing no injuries but damaging three rooms in the school.