BENTONVILLE (AP) — Authorities in northwest Arkansas said Friday that a yearlong investigation had broken up a major drug ring, resulting in at least 12 arrests and the seizure of more than 20 pounds of methamphetamine.

Connor Eldridge, U.S. attorney for the Western District of Arkansas, said the investigation began last year, with the first arrest coming in December when Arturo Vaca-Raya of Springdale was caught with 15 pounds of methamphetamine. Vaca-Raya was sentenced last month to 40 years in prison.

The probe continued, and a wave of arrests followed Monday, with seven people facing charges in federal court and four charged in state court. Agents on Monday seized six pounds of methamphetamine, $18,845 and two firearms.

State, local and federal agencies combined efforts in the investigation.

William J. Bryant, Assistant Special Agent in Charge of the Drug Enforcement Administration, said the busts took a significant amount of methamphetamine out of circulation.

"This investigation is a prime example of outstanding teamwork between federal, state, and local agencies in targeting major drug-trafficking organizations involved in the distribution of methamphetamine," Bryant said.

Eldridge said drug sellers remain a threat in the community.

"These criminal enterprises bring crime into our communities and drugs onto our streets. We will remain vigilant in investigating and prosecuting this activity," Eldridge said.

It wasn’t immediately clear whether any of the defendants have secured lawyers. Charges include conspiracy to distribute methamphetamine, possession with intent to distribute methamphetamine and distribution of methamphetamine.