Tina Durham and Joseph Powell testified Wednesday in Georgetown in the penalty phase of the trial of their son Derrick Powell.
Powell faces the death penalty or life in prison for the 2009 murder of police officer Chad Spicer.
Powell's parents described a family environment that included their drug abuse, frequent arguments and physical violence. Both said Powell was the target of physical and verbal abuse when he was a child.
On Tuesday, prosecutors called two felons to testify as they argued for the death penalty for Powell.
The Cumberland, Md. man was convicted last week.