By Lisa Maria Garza
DALLAS (Reuters) - A gunman who fatally shot eight people at a Dallas-area house knew at least some of the victims gathered there to watch a football game, authorities said on Monday.
The shooter in Plano, Texas, was killed by the first police officer to arrive at the scene on Sunday, Plano Police Chief Gregory Rushin said at a news conference.
The officer discovered seven victims who had been fatally shot, and two others were taken to a hospital. One of those victims later died, Rushin said, adding he did not know the condition of the second person who was hospitalized.
"We've never seen anything like this in this city before," Rushin said.
Authorities did not release the identities of the victims or the shooter. All the people who died in the shooting were adults in their 20s and 30s and the victims were of both genders, Rushin said.
The mass shooting occurred during a cookout at the house, as people gathered there to watch the Dallas Cowboys season opening game on television, Rushin said.
A police officer arrived at the home less than three minutes after an emergency call was made.
He heard gunshots coming from inside the property and found some victims lying in the back yard. The officer went into the house alone, before backup could arrive, and shot the gunman, Rushin said.
The shooter, who had multiple firearms, was "known by people in the residence," Rushin said.
The police officer has been placed on paid administrative leave as authorities investigate his opening fire on the gunman.
Police are not looking for any other suspects. But the investigation is still ongoing, with detectives combing through the crime scene and interviewing witnesses, Rushin said.
(Additional reporting by Alex Dobuzinskis in Los Angeles; Editing by Andrew Hay and Alistair Bell)