Vanessa Gay, 37, who agreed to be identified in the news media, said she met Sowell on the street in 2008 and agreed to come home with him to celebrate his birthday, WJW-TV, Cleveland, reported. But she said he turned on her soon after they got to the house, hitting her and yelling at her.
"He told me if I didn't do what he told me to do to a tee, he was gonna throw me in a closet and forget about me," she said.
Sowell's trial began Monday in Cuyahoga County Common Pleas Court. The 51-year-old is charged with the aggravated murder of 11 women whose bodies were found in his house or buried in the yard, and with kidnapping, abuse of a corpse and tampering with evidence.
Gay said she saw the body when Sowell left the room where he had repeatedly attacked her. He eventually let her leave.
When she called police, she was told she would have to report the sexual assault at the police station, she said. Because of her injuries, she did not go and only told police about it after the bodies were found in 2009.
Gay admitted she was a crack addict in 2008 but said she has turned her life around.
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'
Exploding whale video goes viral on Internet