A suspect was arrested after officers discovered over $8 million worth of fentanyl pills inside his truck.

The suspect, who only identified as a 23-year-old man, was attempting to cross the border into the U.S. from Mexico on Nov. 3 at around 9:55 a.m.

He was driving an older-model 1995 pickup truck to the Calexico West Port of Entry, according to U.S. Customs and Border Protection.

His truck was moved to an inspection area where an imaging scan detected “irregularities” within the vehicle, authorities said. A K-9 was brought to the scene where officers received a “positive alert to the presence of narcotics.”

While examining the man’s truck, officers found 41 packages concealed inside the vehicle’s spare tire and rear seat area.

The packages contained around 840,000 blue pills that tested positive for fentanyl. 

The total weight of the packages was 185.41 pounds. Authorities estimated the street value of the pills at $8.4 million.

The fentanyl pills and pickup truck were seized by border patrol officers while the driver was turned over to Homeland Security Investigations.

Fentanyl is a “synthetic opioid, approved for treating severe pain, typically advanced cancer pain. It is also 50 to 100 times more potent than morphine,” according to the Centers for Disease Control and Prevention.

Illegally-made fentanyl, usually mixed with heroin or cocaine, is the leading cause of overdoses and deaths in the United States.

“Fentanyl continues to be the deadliest drug threat our nation has ever encountered,” said Roque Caza, Calexico Area Port Director. “This seizure is indicative of the exceptional performance our officers display day after day. Their vigilance and dedication are vital assets that make a significant difference in our communities.”

The number of fentanyl-related deaths in Southern California has skyrocketed over the past six years, with the ongoing crisis prompting an outcry from local lawmakers and victims’ families for stricter laws and penalties concerning fentanyl.