Federal marshals arrested Dwayne Greene early Sunday without incident.
Police say 33-year-old Freddie Jackson was shot outside an apartment Tuesday afternoon, and 48-year-old Laura Dowdy was shot at her home early Saturday.
Dowdy lived near the spot where Jackson was killed.
Police say an investigation showed Jackson's death was linked to a drug deal, and the woman's killing was related to Jackson's killing.
Greene is being held in the Chatham County jail.