ABC News

ABC News' Alex Perez reports:

Silver haired and sweet faced, Darlene Mayes looks like many grannies but according to police, she is one of Oklahoma's biggest drug kingpins.

Her operation went up in smoke this week, when police entered her home and found 4 pounds of pot and $276,000 cash.

Police found $15,000 bundles of cash stashed away in the home.

Mayes initially told police the money was part of her retirement fund.

Police also say she was packing a semiautomatic pistol and a revolver.

Investigators say her alleged pot-dealing network spanned four states, from Tulsa, Okla., to Arkansas, Kansas, and Missouri.

Police believe she supplied up to 40 percent of the marijuana in that area.

As the mastermind, police believe she had a network of dealers, including her son Jerry who was also arrested.

Law enforcement expert Brad Garrett says harmless looking seniors can sometimes be the most efficient drug dealers.

"It doesn't surprise me that someone this age would be actively involved in marijuana distribution because there's just too much money to be made. If they keep a low profile, they don't talk to many people, and they don't get greedy, they can go on for years."

Mayes is not the first grandmother accused of ditching retirement for a second career in drug dealing.

In the United Kingdom, 68-year-old Patricia Tabram-dubbed the cannabis grandma-was charged with intent to supply after authorities say they found a marijuana farm in her home.

In Tennessee, an elderly couple was busted for selling prescription drugs.

But the granddaddy of all drug dealers may be  Francis Cook, 83, also known as Britain's oldest drug dealer.