HARRIS COUNTY, TX — A 20-year-old has been arrested for allegedly stabbing his great-grandparents and Texas authorities say it was a 12-year-old boy who jumped in to stop the assault.
Suspect Lucian Johnston was in the car with his great-grandparents Sunday night when an argument broke out, according to the Harris County Sheriff's Office.
Johnston, who was sitting in the back seat, allegedly took a pocket knife and started stabbing his great-grandparents in the head and neck, officials said.
A 12-year-old relative who was also in the back seat "managed to wrestle the knife away from Johnston & threw it out the window, which successfully stopped the attack," Harris County Sheriff Ed Gonzalez tweeted Monday.
The sheriff called the 12-year-old a "hero" who "truly prevented a double-murder."
The victims -- a 92-year-old woman and a 76-year-old man -- suffered non-life threatening wounds and are expected to fully recover, officials said.
But Johnston fled the scene and was at-large through the night, authorities said.
Police were searching for Johnston Monday morning in a subdivision when he was spotted behind a home; he was taken into custody without incident, sheriff's officials said.
Johnston faces two counts of aggravated assault with a deadly weapon, authorities said. Johnston is due in court on Tuesday.