Police found the bodies of four adults inside an upscale suburban Chicago (search) home, some of them with severe trauma injuries, authorities said.

No weapons were found in the home, but homicide-suicide had not been ruled out, Police Lt. Rusty Sullivan (search) said.

Sullivan declined to say when or how the victims died, except to say some had "severe" blunt force trauma. Autopsy results were expected Friday.

Officers were called to the two-story brick house to check on the residents when they did not show up for work Thursday. One body was found on the first floor and the three others elsewhere inside the home.

An initial investigation showed no sign of forced entry, Sullivan said.

Among people authorities want to question, at least one is in California (search), Sullivan said. He declined to describe anyone on the list as a suspect. A house in nearby Naperville was also a target of the investigation, Sullivan said. He declined to provide details.

Federal and out-of-state agencies, including on the West Coast, were called to assist in the investigation, although Sullivan declined to elaborate.

Thomas Kosanda, who lives next door, identified the couple who live in the home as James and Kate Tsao. He said they have no children.

"They were just a real good couple," he said. "Kate loved gardening and used to spend a lot of time on her flower beds."

A longtime friend, Mike Cortino, said Tsao came to the United States as a sixth-grader and runs an import-export company, TTT Inc., that ships used computer equipment to Taiwan, where he said Tsao's parents still live.

With the home cordoned off by police tape, neighbors congregated on the street talking about how safe the subdivision normally is with its 24-hour security.

"The kids walk to school alone. That shows you how much trust we have in this neighborhood, so this is very, very unusual," Esin Buche said.

Sullivan said the investigation so far suggested no threat to the community.