D.C. police have filed charges in three homicides, including the killing of a 15-year-old boy Monday.

Eugene Antoine Kelly, 26, of the 300 block of Oneida Street NE was arrested Wednesday and charged with first-degree murder in the shooting of Isaiah Harris, 15, police said.

Harris, the District’s youngest homicide victim this year, was shot in the 1400 block of New Jersey Avenue NW about 10:15 p.m. Monday, police said. Before the shooting, Kelly told a witness that someone had killed his brother and “someone’s gonna pay — I’m gonna go get my gun,” according to court papers filed Thursday.

Kelly was ordered held without bond Thursday pending a July 11 hearing.

Separately, police said Patricia Ann Cave, 45, of Northeast was charged with second-degree murder in the stabbing of Lamont Warren, 36. The incident occurred in the 700 block of 24th Street NE just after 1 a.m. Thursday. Cave was arrested shortly afterward.

In the third case, police announced charges against a man who was already incarcerated on an unrelated charge.

Monquel N. Cook, 21, is accused of felony murder in the shooting of Michael Milton, 47. Milton was gunned down Aug. 22 in the 4200 block of South Capitol Street SE.

Cook is the second person to be charged in Milton’s death: A male juvenile was arrested on murder charges shortly after the shooting.