A 29-year-old man who allegedly wounded two relatives as well was killed in the confrontation, the Fort Worth (Texas) Star-Telegram reported. Investigators late Thursday were unsure if he killed himself or was killed when Officer Kevin James returned fire.
James took a bullet in his left arm. He was reported to be in good condition.
"God was on our side," Justin Police Chief Bill Brooks told reporters outside the Texas Health Harris Fort Worth Hospital.
Judy Gonzalez of Denton County Emergency Services said the first call was about a suicidal person, followed by a report of two men being shot. She said the shooter began firing at James when the police officer arrived at the scene.
Brooks said James has been a police officer for 20 years, the last four in Justin, just outside Fort Worth.