Anne Pressly, 26, was found unconscious in her bed on 20 October with severe head and body wounds. She failed to recover from the horrific injuries and was declared dead at St. Vincent Infirmary Medical Center in Arkansas five days later.
Her murder came just a week after the release of Stone's George W. Bush biopic, in which she plays a news reporter.
Local authorities have now arrested 28-year-old Curtis Vance on suspicion of the slaying.
Police spokesman Lieutenant Terry Hastings confirmed Vance had been taken into custody on Wednesday night, after cops were alerted to his location following a late-night news conference, where he was revealed as the key suspect.
It had been feared Vance was armed with a pistol and "lots of extra ammunition", but he was found unarmed when cops swooped on his home in Little Rock.
Vance has been charged with capital murder based on "a very, very solid case due to solid detective work", the representative said. However, the authorities have refused to go into further detail about what led them to name Vance as their main suspect.