Police armed with assault-type rifles and attired in helmets and bulletproof vests, greeted morning commuters traveling through Butler this morning.

At the center of the drama was an apartment building at 120 W. Pearl St., where a man in his late 30s or early 40s allegedly threatened to kill another tenant, authorities said.

Butler police were able to evacuate everyone, except the suspect, from the two-story brick building. There are four units, all occupied.

The standoff began when the man would not come out of his apartment and would not speak to officers or answer his telephone.

Authorities did not immediately know if the man had a gun. They could not rule out if he had been drinking.

Police cordoned off a large perimeter that encompassed North Main, north Jackson and West Pearl streets.

Police Chief Tim Fennell called in the state police Special Emergency Response Team to help,