PROVIDENCE, R.I. (WPRI) — U.S. Attorney for Rhode Island Zachary Cunha announced Monday the seizure of more than 660,000 counterfeit pills containing methamphetamine.

Dylan Rodas, 27, of Cumberland, was arrested and charged in the case, which authorities believe is the single biggest seizure of fake Adderall pills in the country.

Rodas is charged with possession with intent to distribute 500 grams or more of methamphetamine.

The seizure was the result of an ongoing, months-long investigation, according to Cunha. The Drug Enforcement Administration (DEA) conducted searches at two locations in Cumberland where they seized approximately 660,500 fake Adderall pills, or 660 pounds, and a bucket of 40 pounds of methamphetamine mixture.

“That’s roughly the weight of a V8 car engine or a baby grand piano,” Cunha noted.

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The pills have an estimated street value of $4.6 million, authorities said.

Around 1,000 pills contained fentanyl. Authorities also recovered 11 kilograms of methamphetamine powder, 250 grams of crack cocaine, $15,000 in cash and seven handguns, including two ghost guns and two guns with obliterated serial numbers.

The handguns will be destroyed.

Rodas has agreed to plead guilty, according to Cunha. If the court accepts the deal, he will serve at least 10 years in federal prison.

Cunha said his office will continue to combat the proliferation of drugs on the streets and gave a word of warning to Rhode Islanders.

“If you or a loved one are buying or taking pills off the street or from a friend or from anywhere that is not a pharmacy or a physician, the odds are that it’s not what you think,” Cunha said. “And if whatever you get is laced with fentanyl, that pill may be the last thing you take.”

The bust represents the threat the opioid epidemic poses on the region, according to Cunha.

“It is no secret that Rhode Island and New England at large is suffering from an epidemic of opioid abuse and opioid deaths that continues to run into record numbers,” Cunha said.

Tim White contributed to this report.