FALL RIVER — A black plastic case resembling a briefcase forced the evacuation of about 100 city employees from Government Center yesterday, but a state police bomb squad opened the case and determined it was not dangerous.

Shortly after 1 p.m., Jim Smith, the city director of municipal services, noticed the case on the exterior steps of Government Center, which houses city departments and offices including the mayor’s office. the The case was near the entrance across from the post office, he said. No one claimed ownership and Smith informed a police officer stationed at the center, who alerted Fall River police. The police called in a state police bomb squad.

Smith said city employees evacuated from an exit on the opposite side from the case. The area was cordoned off and employees gathered in a bank parking lot at Third Street and Sullivan Drive, roughly 100 feet from Government Center. The building remained empty for about one hour and 20 minutes, Smith said.

The police do not know who owns the case, and they are continuing to investigate, Smith said. He said the case looked like a briefcase — it had a handle — and was made of plastic. He said investigators found video camera equipment inside the case.

“It looked more like a case that would hold a drill or tools rather than paper and stuff,” said Smith.