Defense attorney David S. Rudenstein had argued that Damon was not guilty by reason of insanity.
Assistant District Attorney Thomas H. Lipscomb said the guilty verdict on first-degree murder carries a mandatory life prison term without parole. Geroff, however, delayed formal sentencing until May 13 to give officials time to find the appropriate facility for Damon to serve her sentence.
Police went to Lee's house in the 6000 block of Cobbs Creek Parkway after reports of gunfire about 5:10 a.m. Arriving officers found heavy smoke billowing out of the first floor and firefighters spent about 15 minutes bringing the blaze under control.
Inside the kitchen, police found Lee, 53, shot twice in the chest and burned beyond recognition. Two other people in the house escaped without being shot but a woman was severely burned.
That woman, Kelly Winters, died in 2011 after surgery on burn-related injuries, Lipscomb said.
The other person who escaped, Don Harmon, Lee's boyfriend, testified at trial, Lipscomb said.
After setting the house of fire, Damon fled to Maryland and police arrested her near her home in Hagerstown. For much of the time since then, Damon has been in Norristown State Hospital, where she received psychiatric treatment until she was found mentally competent to stand trial.
Although Damon is severely mentally ill, Lipscomb said, the evidence showed that she planned the killing, bought a gun and took shooting lessons before the killing.