The man charged with fatally shooting his mother and half brother inside their Fort Washington home last summer was convicted of second-degree murder and other related counts Thursday, prosecutors said.

Quindell Mercer, 35, faces 110 years in prison at his sentencing in January, prosecutors said. He was convicted of two counts of second-degree murder and related gun charges in the August 2011 slayings of 20-year-old Frank Lamar Harris and 56-year-old Patricia Harris inside their Fort Washington home, prosecutors said.

Prosecutors had accused Mercer of fatally shooting Patricia, his mother, and Frank, his half brother, then leaving them dead on a couch where Patricia’s husband eventually found them.

Mercer’s trial lasted throughout last week. His sentencing is scheduled for Jan. 11, prosecutors said.