Houston man accused of stabbing great-grandparents found with knife in jail, according to sheriff

Lucian Adrian Johnston, 20, has been charged with possession a prohibited weapon in a correctional facility. It was discovered that Johnston concealed a small knife into HCSO detention facility, according to an HCSO news release. The Harris County Sheriffs Office of Inspector General is conducting an internal investigation. less Lucian Adrian Johnston, 20, has been charged with possession a prohibited weapon in a correctional facility. It was discovered that Johnston concealed a small knife into HCSO detention facility, according to an ... more Photo: Harris Co. Sheriff's Office Photo: Harris Co. Sheriff's Office Image 1 of / 1 Caption Close Houston man accused of stabbing great-grandparents found with knife in jail, according to sheriff 1 / 1 Back to Gallery

A Houston man accused of stabbing his great-grandparents with a pocketknife while they were driving was allegedly found with another knife in his possession in jail, according to the Harris County Sheriff's Office.

Lucian Adrian Johnston, 20, has been charged with possession of a prohibited weapon in a correctional facility. Johnston concealed a small knife smuggled into HCSO detention facility, according to an HCSO news release. The Harris County Sheriffs Office of Inspector General is conducting an internal investigation.

RELATED: 12-year-old stops back-seat knife attack of great-grandparents near Katy, sheriff says

Johnston was charged earlier in the week with two counts of aggravated assault with a deadly weapon, after allegedly stabbing two family members.

His 12-year-old half brother is being hailed as a hero for wrestling the pocketknife away from Johnston as he allegedly stabbed their great-grandparents from the back seat of a moving car, Harris County Sheriff Ed Gonzalez said.

The quick-thinking boy lunged at Johnston and wrestled the knife away before grabbing and tossing it out the window of the moving car, according to Gonzalez.

Johnston was already being held on a $100,000 bond. An additional $40,000 bond was added for the new charge.

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