A business meeting turned deadly when a gunman apparently angry over money killed three men and critically injured a fourth before exchanging gunfire with police and then killing himself, police said.
No police officers were hurt in Monday night's exchange of gunfire at an office park, city police Deputy Commissioner Richard Ross said.
Police, who entered a conference room about 100 yards (meters) from the gunfight and found the bodies, described the scene as "utter chaos," he said.
"Two of them are on the floor, one of them in a chair, all of whom sustained gunshot wounds to various parts of the body," Ross said.
Two other men who were not shot had been bound with duct tape. One of those men told officers that the gunman had shot himself, Ross said.
"The officer mentioned to me that he had to take a knife out to cut this person loose," Ross said.
Police did not release the names of those involved, but Ross said Monday night that all appeared to be in their 30s or 40s.
Police were not immediately sure what the name of the business was but it was believed to be an investment firm, Ross said. The gunman's role in the company was not immediately clear, but Ross said police believed he might have been an investor.
The shootings took place in the Philadelphia Naval Business Center, an office park that is part of the old Philadelphia Navy Yard.
It was one of the Navy's busiest shipbuilders during World War II but closed in 1995. Two years later, a private company, Kvaerner, resumed commercial shipbuilding in a portion of the shipyard, which is now known as Aker Shipyard. Other areas of the Navy facility have been converted to business and office use.