Washington, D.C., police have arrested a suspect in connection to the Mother’s Day killing of 10-year-old Arianna Davis.

On Monday, D.C. police said they had arrested Karon Gregory, 19, and charged him with first-degree murder while armed.

Davis was shot in the upper body while driving home with her family following Mother's Day celebrations. D.C. Police said in May that Davis was "accidentally hit in a barrage of gunfire." She died in a local hospital days later.

Metropolitan Police Department Assistant Chief of Police Carlos Heraud told reporters on Monday: “What we know so far is we believe that this suspect and at least one other individual exchanged gunfire.”

Police told reporters that the investigation is ongoing, and they plan to “hold everybody accountable for their actions,” Hearaud said.

Acting Police Chief Pamela Smith urged the public to continue to share tips to help solve this alleged murder.

“The reward remains at $45,000 for information leading to the arrest and conviction of the persons responsible for Arianna’s death,” Smith said on Monday.

ABC News was unable to immediately determine if Gregory had legal representation.