What to Know Lone officer arrives, hears gunshots, sees victims "down" and engages and fatally shoots the suspected gunman.

Seven died at the home Sunday, one victim later died at an area hospital. One survivor remains hospitalized in an unknown condition.

Police say the shooting is an isolated incident and that they are not looking for any other suspects in the case.

Nine people are now dead and one critically injured after someone went on an "unprecedented" shooting rampage at a Plano home Sunday night during a cookout and Dallas Cowboys watch party, police say.

Nine people are now dead and one remains critically injured after someone went on a shooting rampage inside a Plano home Sunday night during a cookout and Dallas Cowboys watching party, police say.

Plano Police Officer David Tilley said officers were called to a home on the 1700 block of West Spring Creek Parkway just after 8 p.m. after several people called 911 reporting active gunshots.

Nine people were shot and killed Sunday, including a suspect, and one other person was critically wounded when someone opened fire inside a Plano home during a Dallas Cowboys watching party, police say.

Plano Chief of Police Gregory Rushin said during a news conference Monday afternoon that the first officer arrived at the home within two minutes of being dispatched. Rushin said the officer approached the home from the rear and heard gunshots inside as well as several shooting victims "down" in the back yard. Rushin said the officer then made the brave decision to enter the home without waiting for backup.

Plano police and the Texas Rangers work the scene of a shooting at a home in the 1700 block of West Spring Creek Parkway in Plano, Texas Monday, September 11, 2017. Seven people were fatally shot to death, and their attacker was killed by a police officer Sunday night. (David Woo/The Dallas Morning News)

"The first thing he heard was shots being fired. He saw people in the back yard, down, that were shot. So he instantly knew what was going on. He went into the house on his own, made that decision that he couldn't wait for a backup from another partner, as we were trained, and go in and to stop the shooter. And that's exactly what he did, he actually found the shooter inside and ended his shooting spree," Rushin said. "This officer went directly into fire, where fire was taking place, and stopped the shooter's ability to continue to kill people. I think the officer showed great bravery."

Inside the home, officers found two survivors, both critically injured with apparent gunshot wounds, and the bodies of seven adults. At a news conference Monday afternoon, police said one of the two survivors died at the hospital, while the condition of the other was not known.

Eight people were shot and killed Sunday, including a suspect, and two others were critically wounded when someone opened fire inside a Plano home during a Dallas Cowboys watching party, police say.

None of the victims have been identified, and any relation to the suspected shooter has not been confirmed, police said, though the suspected shooter was known by people at the residence and had ties to the home. Rushin added the shooting was an isolated incident and that police are not looking for any other suspects in the case.

A motive for the shooting has not been confirmed. Officials said Monday that the shooter used a number of different firearms in the assault and shot people both inside the home and in the back yard. Rushin refused to say whether there were any other survivors of the shooting, citing the integrity of the ongoing investigation.

The parents of Meredith Hight told NBC 5 that she owned the house on Silver Creek Parkway with her husband and that the two were going through a divorce. Monday would have been their wedding anniversary.

Hight's parents say she was hosting a football watch party. A friend of Hight's husband who asked to remain anonymous, said he saw Hight's husband at a nearby bar before the shooting and that he seemed upset.

"Just out of nowhere I heard gunfire but it was rapid fire," said neighbor Crystal Farley. "After the gunfire when you hear the sirens, when the helicopters were coming in I knew something big was up and heart just my stomach just sank," she said.

"That man is a hero and may peace be with him to have to walk into such a scenario and neutralize the suspect," Farley said.

Neighbor Stacey Glover told The Dallas Morning News that a party at the home had started early in the afternoon and she had seen people laughing and grilling outside. She said she then heard the shots around 8 p.m. She opened her door and smelled gunpowder. She heard police who arrived yell "hands up" before more shots rang out.

Neighbor Lauryn Nichols said she had a friend who had been in the house and she didn't know what had happened to the person.

"I'm worried," she told the newspaper. "It's like one big family here."

Eight people are dead, including the suspect, and two are critically wounded after a shooting at a home in Plano.

The investigation into the deaths of the eight victims is being handled by the Plano Police Department. The officer who fatally shot the suspected gunman is on administrative leave with pay and the shooting is being investigated by the Texas Rangers, as is normal in these situations.

Plano officials described the shooting as "unprecedented" and as something beyond anything they thought they ever would have to respond to. Rushin asked for patience in the investigation as the size of the crime scene and nature of the investigation is unlike anything the department has seen. He added that his department is thin, having recently sent officers to the Texas Gulf Coast to support recovery efforts following the landfall of Hurricane Harvey.

Police said Monday afternoon that W. Spring Creek between Green Oaks and Blue Ridge will be closed until possibly Tuesday morning while the homicide investigation continues.

Plano police say seven people have been killed inside a Plano home along West Spring Creek Parkway. Officers say they shot and killed the suspected gunman when they arrived on scene, making a total of 8 people dead.

This story is developing. Check back and refresh this page for the latest updates. NBC 5's Tim Ciesco, Ben Russell, Vanessa Brown, Matt Jackson and Frank Heinz contributed to this report.