The Montgomery County District Attorney's Office and its law enforcement partners have been confiscating a lot of marijuana lately - nearly $15 million of it, actually, in an investigation called Operation: Weed Whacker.

District Attorney Risa Vetri Ferman announced Thursday the dismantling of a major marijuana trafficking ring that saw 3,673 pounds of marijuana - with a street value in Pennsylvania of $14.7 million - shipped in from January to April by a California supplier. It was sent to a pair of Philadelphia-area brothers, who allegedly then sold the drug to dealers throughout Southeastern Pennsylvania.

"The significance of this investigation is truly massive," Ferman said at a news conference, surrounded by tables and crates of marijuana, cash, and other items seized in the probe.

Eight people have been charged.

Ferman said the ring's kingpins were brothers Dennis Frederick, 40, of Drexel Hill, and Jeffrey Frederick, 32, of Philadelphia. The California supplier allegedly was Charles Sadrin, 57, of Lincoln, Calif.

Sadrin and the Fredericks are charged with manufacture, delivery, or possession of controlled substances; corrupt organizations; and related charges.

The investigation began in September when Ferman's Narcotics Enforcement Team targeted trafficking of "high-grade" marijuana in Whitpain Township, Ferman said.

In November, detectives learned that the Frederick brothers were the local source of the marijuana that was being distributed in Montgomery County and around the region. Law enforcement authorities got authorization last month to place wiretaps on the Fredericks' cellphones.

That's how investigators pinpointed Sadrin in California.

Sadrin allegedly packed the marijuana in large steel tool chests and used a freight service to transport them from Sacramento to Philadelphia. He then would fly to Philadelphia and allegedly deliver the containers to Dennis Frederick at a Sigel Street garage in Philadelphia. After the containers were unloaded, Sadrin sent them back to California via the freight service.

Detectives knew of one of the deliveries and busted the ring on May 7, in mid-transaction, inside the Sigel Street garage.

Seized that day in the garage, and at residences and in vehicles of other suspects identified as involved in the ring, were a total 400 pounds of marijuana, which could sell on the streets for $4,000 per pound, about $689,000 in cash, four firearms, seven vehicles, and more than 30 cellphones.

Sacramento police and Montgomery County detectives also have seized money and drugs in California in the investigation of Sadrin and $20,000 in cash from a safe-deposit box and a marijuana-growing operation in a garage there. Some aspects of the investigation are continuing, said Jason Whalley, one of the county prosecutors on the case.

Contact Carolyn Davis

at 610-313-8109, cdavis@phillynews.com, or @carolyntweets on Twitter.