A Russian drug called phenazepam may be responsible for nine deaths in Tarrant County, including four in the past three months. 

The tranquilizer turned up in toxicology tests of William Brawley, who died in a car crash in January. Brawley's parents believe their 18-year-old son took phenazepam thinking it was Xanax, resulting in his fatal accident. 

Spokesman for U.S. Drug Enforcement Administration in Dallas, Tim Davis, says agents have seen a growth in phenazepam use in North Texas.

Read this article for more information about the dangerous street drug.