HOUSTON -- Harris County sheriff's deputies fatally shot a teenager who stabbed three people, including a baby, in east Harris County, officials told KPRC Local 2.

Deputies said a 19-year-old stabbed a man, woman and a baby at a home on Tregarnon Drive near Grand Oaks Boulevard at about 7:30 p.m. Wednesday.

Neighbors said the 19-year-old stabbed his father, his brother's girlfriend and his niece, believed to be about 3 months old.

Investigators said a wrecker driver who lives in the area saw the father stumbling outside the home. She called a deputy friend of hers, who relayed everything to the dispatchers.

"I did notice the son," wrecker driver Andrea Rogers said. "It was a large kitchen knife. He (the father) fell to the ground and he (the son) just kept repeatedly stabbing him. It was horrible."

Harris County Sheriff's Office spokeswoman Christina Garza said the deputy, who had been with the department for six years, told the teen several times to put down the knife.

"I heard the officer ask him to put down his weapon numerous times," Rogers said. "He wouldn't do it. He kept walking toward the officer with the knife in his hand and that's when he was shot."

Garza said the deputy fired multiple times. The teen was taken to Lyndon B. Johnson Hospital, where he died. His name was not released.

Garza said investigators didn't know if the teen had any prior convictions. She said it was the first time this deputy had been involved in a shooting.

The victims were taken by medical helicopter to Memorial Hermann Hospital. The man was in critical condition. The woman and baby's conditions were not released.

A neighbor who talked to relatives said the adults were in stable condition on Thursday afternoon and the baby could be released soon.

"It was just like a normal family. You never would see any arguing or nothing," neighbor Georgia Sessum said.

Neighbors said the teen was the father of two children.