PAWLEYS ISLAND, S.C. - A yearlong investigation by federal, state and local agencies into heroin sales on the South Carolina coast has resulted in 21 arrests.

The arrests came Wednesday and Thursday as authorities served warrants in Horry and Georgetown counties and raided a home in Pawleys Island.

Authorities say that agents seized handguns, $12,000 and quantities of crack and powder cocaine.

They also seized heroin, marijuana packaged for sale and several marijuana plants.