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Border officials in California have seized nearly 500 packages of meth and fentanyl worth more than $8 million in just five days.

The seizures were made between July 13 and July 17 at the Calexico Port of Entry, US Customs and Border Protection (CBP) said in a press release.

Narcotics seized by CBP.

Narcotics seized by CBP.

Calexico CBP officers found more than 130 pounds of fentanyl on Wednesday, July 13, after noticing the vehicle had been tampered with during the inspection.

The next day, CBP officers found about 230 pounds of fentanyl after a canine enforcement search.

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On Friday, July 15, CBP officers detected approximately 110 pounds of fentanyl using the port’s imaging machine.

The next day, CBP officers searched the vehicle and luggage and found about 70 pounds of fentanyl and more than 2 grams of marijuana.

And finally, on Sunday, July 17, CBP officers using the port’s imaging machines found more than 72 pounds of fentanyl and nearly 190 pounds of methamphetamine.

Drugs seized by CBP officers during inspections.

Drugs seized by CBP officers during inspections.

CBP said the total estimated street value of the narcotics found by Calexico CBP officers is about $8.25 million.

All subjects involved were turned over to US Immigration and Customs Enforcement (ICE), Homeland Security Investigations (HSI) for further investigation. CBP officers seized the narcotics.

Fentanyl, a synthetic opioid, has been the leading cause of overdose deaths across the US in recent years. A dose of just 2 mg is enough to kill a user with zero tolerance, while 60 mg of heroin is considered a lethal dose.

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“Our officers are trained to be alert for something that looks out of place and to watch closely for unusual travel patterns,” Ann Marisich, acting director of CBP’s field operations in San Diego, said in a statement.