Curtis Lopez was convicted of killing his wife in Germantown and beating his 11-year-old stepson to death with a baseball bat.
Lopez, 46, faces life in prison without parole at his sentencing, which is set for April 17.
Montgomery County prosecutors said Lopez used a 30-pound weight and knife to kill his wife, Jane McQuain, 51, inside her Germantown apartment in October 2011. He then lured her son, William, to a wooded area in Clarksburg, where he beat the boy with a baseball bat, crushing his skull into 36 pieces, according to prosecutors.
Lopez took an Alford plea, meaning that he refuses to admit his guilt, but there is an overwhelming body of evidence that a judge would find him guilty if the case went to trial.