Police in Austin, Texas have arrested a man after finding $4.8 million worth of drugs in his truck tires, the Associated Press reported.

The Austin Police Department’s Organized Crime Division’s Criminal Interdiction Unit stopped a 2004 Ford F-150 for speeding and for failure to display a front license plate, according to a press release from the Austin Police Department.

While speaking with the driver, Armando Martinez, officers cued in on clues that led them to believe the driver may be smuggling illegal narcotics.

Martinez granted officers consent to search his vehicle when officers noted several anomalies around each of the truck’s tires, the release said. Upon further investigation, K-9 “Raggio” positively alerted officers, who discovered around 138 pounds of narcotics hidden in the metal casings of each tire. That included 82 pounds of cocaine, 50 pounds of methamphetamines and six pounds of heroin.

Martinez, 43, was arrested and charged with possession of a controlled substance with intent to deliver. He is currently in jail awaiting transfer to federal custody.