WASHINGTON - Quindell Mercer was convicted of two counts of second degree murder for the deaths of his mother and step-brother, State's Attorney Angela Alsobrooks announced Thursday.
Mercer, 35, of District Heights, was also convicted of using a handgun in the commission of a felony and two counts of possession of a handgun after conviction of a disqualifying crime.
He will be sentenced in January and faces 110 years in prison, the state's attorney's office said.
Mercer was arrested in late August and charged with both first and second degree murder after police say he killed Patricia Harris, 56, and her son, Frank Harris Jr., 20, on Aug. 4 at their Fort Washington home in the 11800 block of Hickory Drive.
"Mr. Mercer executed his mother and step-brother in cold blood for no apparent reason and there is no excuse for this senseless act of violence that took the lives of two of our citizens," Alsobrooks said in a statement. "I am pleased that a jury has held him accountable for his actions and that he will never have the chance to hurt anyone again."
Mercer was tied to the crime by an FBI handwriting expert and DNA evidence that showed it was unlikely that anyone but Mercer used the gun that killed the Harrises.
Evidence presented during trial showed that Mercer went to the Harris' home and shot Patricia and Frank Harris, then posed their bodies on a sofa to make it look like they were sleeping. Investigators don't know why Mercer killed his family members, according to a state's attorney's news release.
Frank Harris Sr., the husband and father of the victims, later found the bodies.
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