Police are searching for a relative of the mother and son shot to death inside their Fort Washington home last Thursday, saying he is a “person of interest” in homicide detectives’ ongoing investigation.

Quindell Mercer, 34, has not been seen or heard from since Patricia Harris, 56, and son, Frank L. Harris, 20, were found shot to death on the main level of their home in the 11800 block of Hickory Drive, said Cpl. Evan Baxter, a Prince George’s County police spokesman. He said detectives are asking anyone who sees Mercer to call 911.

Quindell Mercer (Courtesy Prince George's County Police Department)

No one has been charged in connection with the slayings of the mother and son.

Court records show Mercer has had extensive contacts with police in the past, including convictions in Prince George’s for first-degree assault and carrying a handgun. He is wanted on assault warrants in North Carolina, authorities said.

Law enforcement sources said Mercer is Patricia Harris’s son and Frank Harris’s step brother. Baxter said he did not know their specific relationship.