CLAY COUNTY, Fla. -

Thirty-one people were arrested in Clay County this week on charges of sale of controlled substances and other drug-related charges.

The arrests were the result of a six-month investigation involving street-level narcotic purchases, deputies said.

IMAGES: Mug shots of 31 arrested

They said additional arrests are pending.

Most of the drugs purchased through undercover means were crack cocaine and pharmaceutical grade drugs, deputies said.

They said most of the activity occurred in Green Cove Springs. However, some of the purchases were made in Orange Park and Middleburg.

Deputies said 109 pounds of marijuana were seized.