Michael Mason reportedly conducted the fatal shootings over a 7-week span between April 7 and May 22 in two separate districts, the Metropolitan Police Department said. They added that at least five other people were wounded during the spree.
Mason denied his involvement during interviews with homicide detectives, according to an arrest affidavit. One of the alleged victims included a woman who was used as a “human shield” by a person targeted by a gunman, police said.
Police said the fatal shooting involving one woman, Brea Moon, 21, occurred 11 days after Mason was released from juvenile detention.
Mason was identified after authorities used facial recognition software to compare a photo given by a victim with images of Mason on social media, a court affidavit said, according to the Washington Post. Police added that Mason reportedly tried to sell a .40-caliber gun on Instagram following one of the killings.
Mason was charged as an adult with four counts of first-degree murder, four counts of assault with intent to kill, assault with intent to murder, and assault with a dangerous weapon, police said.
Police also charged Daquan Jones, 19, of Northeast D.C., with first-degree murder in reference to Moon’s killing.
"These individuals terrorized our communities and we thank all who assisted in their arrest," D.C. police wrote on Twitter.
An investigation is ongoing.