Nine people are dead, including the gunman, after he opened fire on a football watching party at a Plano home Sunday night.
Tilley said when police arrived, the first officer to enter the home was involved in a confrontation with the suspected shooter.
Police arrived at the home on Sunday evening after neighbors reported shots being fired.
Two other people were wounded in the shooting, nbcdfw.com reports. All those killed and injured are believed to be adults. The officer saw people with gunshot wounds in the back yard, Rushin said. An internal affairs investigation is underway, he said.
While Plano police are investigating the homicide, the Texas Rangers will investigate the police officer's shooting of the suspect.
More than thirty police units were at the scene at 9:30 p.m.
Dead, Including Suspected Gunman, in Shooting in Texas
Police were called and an officer shot dead the suspected shooter.
"We've never had a shooting of this magnitude", Rushin said.
"I truly wish we knew who alternate casualties were". "As they were arguing, the woman was trying to go back in", she said.
Meredith Lane, 27, was shot and killed at a house in Plano, where she was hosting friends to watch the Dallas Cowboys play the New York Giants, her mother told WFAA.
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