Seven people were found dead and two others seriously injured on Saturday morning in a mobile home in Glynn County, the U.S. state of Georgia.
The county's police chief Matt Doering told a televised news conference that police officers responding to a 911 call of multiple deaths found the victims shortly after 8 a.m. eastern U.S. time (1200 GMT).
However, Doering didn't provide further information about the incident, only saying that a homicide investigation is underway.
The two wounded people found inside the home was given immediate assistance, he added.
Both have been transported to an area hospital for treatment.
Doering declined to say whether there was a suspect in the slayings.
Officers have tentatively identified some of the victims in the afternoon and are in the process of removing some of the bodies, Doering said.
A medical examiner from the Georgia Crime Lab was on the way to begin working on a determination of the causes of the deaths, he said.
Doering characterized the slayings as likely the largest single homicide in the county's history.
TV footages show the mobile home looks dirty from the outside with waste littering on the nearby ground.
Local media reported that a woman came to the scene in a white car by noon, spoke briefly to some residents and then began screaming: "They killed my boy."
She spoke with police officers and left shortly thereafter.
A man who lives next door said he heard dogs barking late Friday night and again Saturday morning but heard no shots or any other alarming sounds.
He said a man who lives in the mobile home came home this morning and came out yelling: "My whole family is dead."